linux/samples/bpf/tracex3_user.c

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// SPDX-License-Identifier: GPL-2.0-only
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
*/
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <stdbool.h>
#include <string.h>
#include <linux/bpf.h>
#include <sys/resource.h>
bpf: fix multiple issues in selftest suite and samples 1) The test_lru_map and test_lru_dist fails building on my machine since the sys/resource.h header is not included. 2) test_verifier fails in one test case where we try to call an invalid function, since the verifier log output changed wrt printing function names. 3) Current selftest suite code relies on sysconf(_SC_NPROCESSORS_CONF) for retrieving the number of possible CPUs. This is broken at least in our scenario and really just doesn't work. glibc tries a number of things for retrieving _SC_NPROCESSORS_CONF. First it tries equivalent of /sys/devices/system/cpu/cpu[0-9]* | wc -l, if that fails, depending on the config, it either tries to count CPUs in /proc/cpuinfo, or returns the _SC_NPROCESSORS_ONLN value instead. If /proc/cpuinfo has some issue, it returns just 1 worst case. This oddity is nothing new [1], but semantics/behaviour seems to be settled. _SC_NPROCESSORS_ONLN will parse /sys/devices/system/cpu/online, if that fails it looks into /proc/stat for cpuX entries, and if also that fails for some reason, /proc/cpuinfo is consulted (and returning 1 if unlikely all breaks down). While that might match num_possible_cpus() from the kernel in some cases, it's really not guaranteed with CPU hotplugging, and can result in a buffer overflow since the array in user space could have too few number of slots, and on perpcu map lookup, the kernel will write beyond that memory of the value buffer. William Tu reported such mismatches: [...] The fact that sysconf(_SC_NPROCESSORS_CONF) != num_possible_cpu() happens when CPU hotadd is enabled. For example, in Fusion when setting vcpu.hotadd = "TRUE" or in KVM, setting ./qemu-system-x86_64 -smp 2, maxcpus=4 ... the num_possible_cpu() will be 4 and sysconf() will be 2 [2]. [...] Documentation/cputopology.txt says /sys/devices/system/cpu/possible outputs cpu_possible_mask. That is the same as in num_possible_cpus(), so first step would be to fix the _SC_NPROCESSORS_CONF calls with our own implementation. Later, we could add support to bpf(2) for passing a mask via CPU_SET(3), for example, to just select a subset of CPUs. BPF samples code needs this fix as well (at least so that people stop copying this). Thus, define bpf_num_possible_cpus() once in selftests and import it from there for the sample code to avoid duplicating it. The remaining sysconf(_SC_NPROCESSORS_CONF) in samples are unrelated. After all three issues are fixed, the test suite runs fine again: # make run_tests | grep self selftests: test_verifier [PASS] selftests: test_maps [PASS] selftests: test_lru_map [PASS] selftests: test_kmod.sh [PASS] [1] https://www.sourceware.org/ml/libc-alpha/2011-06/msg00079.html [2] https://www.mail-archive.com/netdev@vger.kernel.org/msg121183.html Fixes: 3059303f59cf ("samples/bpf: update tracex[23] examples to use per-cpu maps") Fixes: 86af8b4191d2 ("Add sample for adding simple drop program to link") Fixes: df570f577231 ("samples/bpf: unit test for BPF_MAP_TYPE_PERCPU_ARRAY") Fixes: e15596717948 ("samples/bpf: unit test for BPF_MAP_TYPE_PERCPU_HASH") Fixes: ebb676daa1a3 ("bpf: Print function name in addition to function id") Fixes: 5db58faf989f ("bpf: Add tests for the LRU bpf_htab") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: William Tu <u9012063@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-26 01:28:09 +01:00
#include <bpf/bpf.h>
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
#include "bpf_load.h"
bpf: fix multiple issues in selftest suite and samples 1) The test_lru_map and test_lru_dist fails building on my machine since the sys/resource.h header is not included. 2) test_verifier fails in one test case where we try to call an invalid function, since the verifier log output changed wrt printing function names. 3) Current selftest suite code relies on sysconf(_SC_NPROCESSORS_CONF) for retrieving the number of possible CPUs. This is broken at least in our scenario and really just doesn't work. glibc tries a number of things for retrieving _SC_NPROCESSORS_CONF. First it tries equivalent of /sys/devices/system/cpu/cpu[0-9]* | wc -l, if that fails, depending on the config, it either tries to count CPUs in /proc/cpuinfo, or returns the _SC_NPROCESSORS_ONLN value instead. If /proc/cpuinfo has some issue, it returns just 1 worst case. This oddity is nothing new [1], but semantics/behaviour seems to be settled. _SC_NPROCESSORS_ONLN will parse /sys/devices/system/cpu/online, if that fails it looks into /proc/stat for cpuX entries, and if also that fails for some reason, /proc/cpuinfo is consulted (and returning 1 if unlikely all breaks down). While that might match num_possible_cpus() from the kernel in some cases, it's really not guaranteed with CPU hotplugging, and can result in a buffer overflow since the array in user space could have too few number of slots, and on perpcu map lookup, the kernel will write beyond that memory of the value buffer. William Tu reported such mismatches: [...] The fact that sysconf(_SC_NPROCESSORS_CONF) != num_possible_cpu() happens when CPU hotadd is enabled. For example, in Fusion when setting vcpu.hotadd = "TRUE" or in KVM, setting ./qemu-system-x86_64 -smp 2, maxcpus=4 ... the num_possible_cpu() will be 4 and sysconf() will be 2 [2]. [...] Documentation/cputopology.txt says /sys/devices/system/cpu/possible outputs cpu_possible_mask. That is the same as in num_possible_cpus(), so first step would be to fix the _SC_NPROCESSORS_CONF calls with our own implementation. Later, we could add support to bpf(2) for passing a mask via CPU_SET(3), for example, to just select a subset of CPUs. BPF samples code needs this fix as well (at least so that people stop copying this). Thus, define bpf_num_possible_cpus() once in selftests and import it from there for the sample code to avoid duplicating it. The remaining sysconf(_SC_NPROCESSORS_CONF) in samples are unrelated. After all three issues are fixed, the test suite runs fine again: # make run_tests | grep self selftests: test_verifier [PASS] selftests: test_maps [PASS] selftests: test_lru_map [PASS] selftests: test_kmod.sh [PASS] [1] https://www.sourceware.org/ml/libc-alpha/2011-06/msg00079.html [2] https://www.mail-archive.com/netdev@vger.kernel.org/msg121183.html Fixes: 3059303f59cf ("samples/bpf: update tracex[23] examples to use per-cpu maps") Fixes: 86af8b4191d2 ("Add sample for adding simple drop program to link") Fixes: df570f577231 ("samples/bpf: unit test for BPF_MAP_TYPE_PERCPU_ARRAY") Fixes: e15596717948 ("samples/bpf: unit test for BPF_MAP_TYPE_PERCPU_HASH") Fixes: ebb676daa1a3 ("bpf: Print function name in addition to function id") Fixes: 5db58faf989f ("bpf: Add tests for the LRU bpf_htab") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: William Tu <u9012063@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-26 01:28:09 +01:00
#include "bpf_util.h"
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
#define SLOTS 100
static void clear_stats(int fd)
{
bpf: fix multiple issues in selftest suite and samples 1) The test_lru_map and test_lru_dist fails building on my machine since the sys/resource.h header is not included. 2) test_verifier fails in one test case where we try to call an invalid function, since the verifier log output changed wrt printing function names. 3) Current selftest suite code relies on sysconf(_SC_NPROCESSORS_CONF) for retrieving the number of possible CPUs. This is broken at least in our scenario and really just doesn't work. glibc tries a number of things for retrieving _SC_NPROCESSORS_CONF. First it tries equivalent of /sys/devices/system/cpu/cpu[0-9]* | wc -l, if that fails, depending on the config, it either tries to count CPUs in /proc/cpuinfo, or returns the _SC_NPROCESSORS_ONLN value instead. If /proc/cpuinfo has some issue, it returns just 1 worst case. This oddity is nothing new [1], but semantics/behaviour seems to be settled. _SC_NPROCESSORS_ONLN will parse /sys/devices/system/cpu/online, if that fails it looks into /proc/stat for cpuX entries, and if also that fails for some reason, /proc/cpuinfo is consulted (and returning 1 if unlikely all breaks down). While that might match num_possible_cpus() from the kernel in some cases, it's really not guaranteed with CPU hotplugging, and can result in a buffer overflow since the array in user space could have too few number of slots, and on perpcu map lookup, the kernel will write beyond that memory of the value buffer. William Tu reported such mismatches: [...] The fact that sysconf(_SC_NPROCESSORS_CONF) != num_possible_cpu() happens when CPU hotadd is enabled. For example, in Fusion when setting vcpu.hotadd = "TRUE" or in KVM, setting ./qemu-system-x86_64 -smp 2, maxcpus=4 ... the num_possible_cpu() will be 4 and sysconf() will be 2 [2]. [...] Documentation/cputopology.txt says /sys/devices/system/cpu/possible outputs cpu_possible_mask. That is the same as in num_possible_cpus(), so first step would be to fix the _SC_NPROCESSORS_CONF calls with our own implementation. Later, we could add support to bpf(2) for passing a mask via CPU_SET(3), for example, to just select a subset of CPUs. BPF samples code needs this fix as well (at least so that people stop copying this). Thus, define bpf_num_possible_cpus() once in selftests and import it from there for the sample code to avoid duplicating it. The remaining sysconf(_SC_NPROCESSORS_CONF) in samples are unrelated. After all three issues are fixed, the test suite runs fine again: # make run_tests | grep self selftests: test_verifier [PASS] selftests: test_maps [PASS] selftests: test_lru_map [PASS] selftests: test_kmod.sh [PASS] [1] https://www.sourceware.org/ml/libc-alpha/2011-06/msg00079.html [2] https://www.mail-archive.com/netdev@vger.kernel.org/msg121183.html Fixes: 3059303f59cf ("samples/bpf: update tracex[23] examples to use per-cpu maps") Fixes: 86af8b4191d2 ("Add sample for adding simple drop program to link") Fixes: df570f577231 ("samples/bpf: unit test for BPF_MAP_TYPE_PERCPU_ARRAY") Fixes: e15596717948 ("samples/bpf: unit test for BPF_MAP_TYPE_PERCPU_HASH") Fixes: ebb676daa1a3 ("bpf: Print function name in addition to function id") Fixes: 5db58faf989f ("bpf: Add tests for the LRU bpf_htab") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: William Tu <u9012063@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-26 01:28:09 +01:00
unsigned int nr_cpus = bpf_num_possible_cpus();
__u64 values[nr_cpus];
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
__u32 key;
memset(values, 0, sizeof(values));
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
for (key = 0; key < SLOTS; key++)
samples/bpf: Make samples more libbpf-centric Switch all of the sample code to use the function names from tools/lib/bpf so that they're consistent with that, and to declare their own log buffers. This allow the next commit to be purely devoted to getting rid of the duplicate library in samples/bpf. Committer notes: Testing it: On a fedora rawhide container, with clang/llvm 3.9, sharing the host linux kernel git tree: # make O=/tmp/build/linux/ headers_install # make O=/tmp/build/linux -C samples/bpf/ Since I forgot to make it privileged, just tested it outside the container, using what it generated: # uname -a Linux jouet 4.9.0-rc8+ #1 SMP Mon Dec 12 11:20:49 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux # cd /var/lib/docker/devicemapper/mnt/c43e09a53ff56c86a07baf79847f00e2cc2a17a1e2220e1adbf8cbc62734feda/rootfs/tmp/build/linux/samples/bpf/ # ls -la offwaketime -rwxr-xr-x. 1 root root 24200 Dec 15 12:19 offwaketime # file offwaketime offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c940d3f127d5e66cdd680e42d885cb0b64f8a0e4, not stripped # readelf -SW offwaketime_kern.o | grep PROGBITS [ 2] .text PROGBITS 0000000000000000 000040 000000 00 AX 0 0 4 [ 3] kprobe/try_to_wake_up PROGBITS 0000000000000000 000040 0000d8 00 AX 0 0 8 [ 5] tracepoint/sched/sched_switch PROGBITS 0000000000000000 000118 000318 00 AX 0 0 8 [ 7] maps PROGBITS 0000000000000000 000430 000050 00 WA 0 0 4 [ 8] license PROGBITS 0000000000000000 000480 000004 00 WA 0 0 1 [ 9] version PROGBITS 0000000000000000 000484 000004 00 WA 0 0 4 # ./offwaketime | head -5 swapper/1;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 106 CPU 0/KVM;entry_SYSCALL_64_fastpath;sys_ioctl;do_vfs_ioctl;kvm_vcpu_ioctl;kvm_arch_vcpu_ioctl_run;kvm_vcpu_block;schedule;__schedule;-;try_to_wake_up;swake_up_locked;swake_up;apic_timer_expired;apic_timer_fn;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary;;swapper/3 2 Compositor;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;futex_requeue;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;SoftwareVsyncTh 5 firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 13 JS Helper;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;firefox 2 # Signed-off-by: Joe Stringer <joe@ovn.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Wang Nan <wangnan0@huawei.com> Cc: netdev@vger.kernel.org Link: http://lkml.kernel.org/r/20161214224342.12858-2-joe@ovn.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-12-14 23:43:38 +01:00
bpf_map_update_elem(fd, &key, values, BPF_ANY);
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
}
const char *color[] = {
"\033[48;5;255m",
"\033[48;5;252m",
"\033[48;5;250m",
"\033[48;5;248m",
"\033[48;5;246m",
"\033[48;5;244m",
"\033[48;5;242m",
"\033[48;5;240m",
"\033[48;5;238m",
"\033[48;5;236m",
"\033[48;5;234m",
"\033[48;5;232m",
};
const int num_colors = ARRAY_SIZE(color);
const char nocolor[] = "\033[00m";
const char *sym[] = {
" ",
" ",
".",
".",
"*",
"*",
"o",
"o",
"O",
"O",
"#",
"#",
};
bool full_range = false;
bool text_only = false;
static void print_banner(void)
{
if (full_range)
printf("|1ns |10ns |100ns |1us |10us |100us"
" |1ms |10ms |100ms |1s |10s\n");
else
printf("|1us |10us |100us |1ms |10ms "
"|100ms |1s |10s\n");
}
static void print_hist(int fd)
{
bpf: fix multiple issues in selftest suite and samples 1) The test_lru_map and test_lru_dist fails building on my machine since the sys/resource.h header is not included. 2) test_verifier fails in one test case where we try to call an invalid function, since the verifier log output changed wrt printing function names. 3) Current selftest suite code relies on sysconf(_SC_NPROCESSORS_CONF) for retrieving the number of possible CPUs. This is broken at least in our scenario and really just doesn't work. glibc tries a number of things for retrieving _SC_NPROCESSORS_CONF. First it tries equivalent of /sys/devices/system/cpu/cpu[0-9]* | wc -l, if that fails, depending on the config, it either tries to count CPUs in /proc/cpuinfo, or returns the _SC_NPROCESSORS_ONLN value instead. If /proc/cpuinfo has some issue, it returns just 1 worst case. This oddity is nothing new [1], but semantics/behaviour seems to be settled. _SC_NPROCESSORS_ONLN will parse /sys/devices/system/cpu/online, if that fails it looks into /proc/stat for cpuX entries, and if also that fails for some reason, /proc/cpuinfo is consulted (and returning 1 if unlikely all breaks down). While that might match num_possible_cpus() from the kernel in some cases, it's really not guaranteed with CPU hotplugging, and can result in a buffer overflow since the array in user space could have too few number of slots, and on perpcu map lookup, the kernel will write beyond that memory of the value buffer. William Tu reported such mismatches: [...] The fact that sysconf(_SC_NPROCESSORS_CONF) != num_possible_cpu() happens when CPU hotadd is enabled. For example, in Fusion when setting vcpu.hotadd = "TRUE" or in KVM, setting ./qemu-system-x86_64 -smp 2, maxcpus=4 ... the num_possible_cpu() will be 4 and sysconf() will be 2 [2]. [...] Documentation/cputopology.txt says /sys/devices/system/cpu/possible outputs cpu_possible_mask. That is the same as in num_possible_cpus(), so first step would be to fix the _SC_NPROCESSORS_CONF calls with our own implementation. Later, we could add support to bpf(2) for passing a mask via CPU_SET(3), for example, to just select a subset of CPUs. BPF samples code needs this fix as well (at least so that people stop copying this). Thus, define bpf_num_possible_cpus() once in selftests and import it from there for the sample code to avoid duplicating it. The remaining sysconf(_SC_NPROCESSORS_CONF) in samples are unrelated. After all three issues are fixed, the test suite runs fine again: # make run_tests | grep self selftests: test_verifier [PASS] selftests: test_maps [PASS] selftests: test_lru_map [PASS] selftests: test_kmod.sh [PASS] [1] https://www.sourceware.org/ml/libc-alpha/2011-06/msg00079.html [2] https://www.mail-archive.com/netdev@vger.kernel.org/msg121183.html Fixes: 3059303f59cf ("samples/bpf: update tracex[23] examples to use per-cpu maps") Fixes: 86af8b4191d2 ("Add sample for adding simple drop program to link") Fixes: df570f577231 ("samples/bpf: unit test for BPF_MAP_TYPE_PERCPU_ARRAY") Fixes: e15596717948 ("samples/bpf: unit test for BPF_MAP_TYPE_PERCPU_HASH") Fixes: ebb676daa1a3 ("bpf: Print function name in addition to function id") Fixes: 5db58faf989f ("bpf: Add tests for the LRU bpf_htab") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: William Tu <u9012063@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-26 01:28:09 +01:00
unsigned int nr_cpus = bpf_num_possible_cpus();
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
__u64 total_events = 0;
long values[nr_cpus];
__u64 max_cnt = 0;
__u64 cnt[SLOTS];
__u64 value;
__u32 key;
int i;
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
for (key = 0; key < SLOTS; key++) {
samples/bpf: Make samples more libbpf-centric Switch all of the sample code to use the function names from tools/lib/bpf so that they're consistent with that, and to declare their own log buffers. This allow the next commit to be purely devoted to getting rid of the duplicate library in samples/bpf. Committer notes: Testing it: On a fedora rawhide container, with clang/llvm 3.9, sharing the host linux kernel git tree: # make O=/tmp/build/linux/ headers_install # make O=/tmp/build/linux -C samples/bpf/ Since I forgot to make it privileged, just tested it outside the container, using what it generated: # uname -a Linux jouet 4.9.0-rc8+ #1 SMP Mon Dec 12 11:20:49 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux # cd /var/lib/docker/devicemapper/mnt/c43e09a53ff56c86a07baf79847f00e2cc2a17a1e2220e1adbf8cbc62734feda/rootfs/tmp/build/linux/samples/bpf/ # ls -la offwaketime -rwxr-xr-x. 1 root root 24200 Dec 15 12:19 offwaketime # file offwaketime offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c940d3f127d5e66cdd680e42d885cb0b64f8a0e4, not stripped # readelf -SW offwaketime_kern.o | grep PROGBITS [ 2] .text PROGBITS 0000000000000000 000040 000000 00 AX 0 0 4 [ 3] kprobe/try_to_wake_up PROGBITS 0000000000000000 000040 0000d8 00 AX 0 0 8 [ 5] tracepoint/sched/sched_switch PROGBITS 0000000000000000 000118 000318 00 AX 0 0 8 [ 7] maps PROGBITS 0000000000000000 000430 000050 00 WA 0 0 4 [ 8] license PROGBITS 0000000000000000 000480 000004 00 WA 0 0 1 [ 9] version PROGBITS 0000000000000000 000484 000004 00 WA 0 0 4 # ./offwaketime | head -5 swapper/1;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 106 CPU 0/KVM;entry_SYSCALL_64_fastpath;sys_ioctl;do_vfs_ioctl;kvm_vcpu_ioctl;kvm_arch_vcpu_ioctl_run;kvm_vcpu_block;schedule;__schedule;-;try_to_wake_up;swake_up_locked;swake_up;apic_timer_expired;apic_timer_fn;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary;;swapper/3 2 Compositor;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;futex_requeue;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;SoftwareVsyncTh 5 firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 13 JS Helper;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;firefox 2 # Signed-off-by: Joe Stringer <joe@ovn.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Wang Nan <wangnan0@huawei.com> Cc: netdev@vger.kernel.org Link: http://lkml.kernel.org/r/20161214224342.12858-2-joe@ovn.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-12-14 23:43:38 +01:00
bpf_map_lookup_elem(fd, &key, values);
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
value = 0;
for (i = 0; i < nr_cpus; i++)
value += values[i];
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
cnt[key] = value;
total_events += value;
if (value > max_cnt)
max_cnt = value;
}
clear_stats(fd);
for (key = full_range ? 0 : 29; key < SLOTS; key++) {
int c = num_colors * cnt[key] / (max_cnt + 1);
if (text_only)
printf("%s", sym[c]);
else
printf("%s %s", color[c], nocolor);
}
printf(" # %lld\n", total_events);
}
int main(int ac, char **argv)
{
struct rlimit r = {1024*1024, RLIM_INFINITY};
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
char filename[256];
int i;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
if (setrlimit(RLIMIT_MEMLOCK, &r)) {
perror("setrlimit(RLIMIT_MEMLOCK)");
return 1;
}
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-25 20:49:25 +01:00
if (load_bpf_file(filename)) {
printf("%s", bpf_log_buf);
return 1;
}
for (i = 1; i < ac; i++) {
if (strcmp(argv[i], "-a") == 0) {
full_range = true;
} else if (strcmp(argv[i], "-t") == 0) {
text_only = true;
} else if (strcmp(argv[i], "-h") == 0) {
printf("Usage:\n"
" -a display wider latency range\n"
" -t text only\n");
return 1;
}
}
printf(" heatmap of IO latency\n");
if (text_only)
printf(" %s", sym[num_colors - 1]);
else
printf(" %s %s", color[num_colors - 1], nocolor);
printf(" - many events with this latency\n");
if (text_only)
printf(" %s", sym[0]);
else
printf(" %s %s", color[0], nocolor);
printf(" - few events\n");
for (i = 0; ; i++) {
if (i % 20 == 0)
print_banner();
print_hist(map_fd[1]);
sleep(2);
}
return 0;
}