When we hit the end of a program block, need to count the last instruction too for the IPC computation. This caused large errors for small blocks. % perf script -b ls / > /dev/null Before: % perf script -F +brstackinsn --xed ... 00007f94c9ac70d8 jz 0x7f94c9ac70e3 # PRED 3 cycles [36] 4.33 IPC 00007f94c9ac70e3 testb $0x20, 0x31d(%rbx) 00007f94c9ac70ea jnz 0x7f94c9ac70b0 00007f94c9ac70ec testb $0x8, 0x205ad(%rip) 00007f94c9ac70f3 jz 0x7f94c9ac6ff0 # PRED 1 cycles [37] 3.00 IPC After: % perf script -F +brstackinsn --xed ... 00007f94c9ac70d8 jz 0x7f94c9ac70e3 # PRED 3 cycles [15] 4.67 IPC 00007f94c9ac70e3 testb $0x20, 0x31d(%rbx) 00007f94c9ac70ea jnz 0x7f94c9ac70b0 00007f94c9ac70ec testb $0x8, 0x205ad(%rip) 00007f94c9ac70f3 jz 0x7f94c9ac6ff0 # PRED 1 cycles [16] 4.00 IPC Suggested-by: Denis Bakhvalov <denis.bakhvalov@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Link: http://lkml.kernel.org/r/20190711181922.18765-2-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
||
---|---|---|
Documentation | ||
LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
README
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.