linux/kernel
Eric Dumazet cd7175edf9 [PATCH] Optimize calc_load()
calc_load() is called by timer interrupt to update avenrun[].  It currently
calls nr_active() at each timer tick (HZ per second), while the update of
avenrun[] is done only once every 5 seconds.  (LOAD_FREQ=5 Hz)

nr_active() is quite expensive on SMP machines, since it has to sum up
nr_running and nr_uninterruptible of all online CPUS, bringing foreign
dirty cache lines.

This patch is an optimization of calc_load() so that nr_active() is called
only if we need it.

The use of unlikely() is welcome since the condition is true only once every
5*HZ time.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-13 09:05:55 -08:00
..
irq [PATCH] CPEI gets warning at kernel/irq/migration.c:27/move_masked_irq() 2006-12-08 08:28:37 -08:00
power [PATCH] PM: Fix SMP races in the freezer 2006-12-13 09:05:49 -08:00
time [PATCH] clocksource: small cleanup 2006-12-10 09:57:22 -08:00
.gitignore
acct.c [PATCH] kernel: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:42 -08:00
audit.c [PATCH] Add include/linux/freezer.h and move definitions from sched.h 2006-12-07 08:39:27 -08:00
audit.h [PATCH] audit: AUDIT_PERM support 2006-09-11 13:32:30 -04:00
auditfilter.c [PATCH] kernel core: replace kmalloc+memset with kzalloc 2006-12-07 08:39:41 -08:00
auditsc.c [PATCH] struct path: convert kernel 2006-12-08 08:28:46 -08:00
capability.c [PATCH] pidspace: is_init() 2006-09-29 09:18:12 -07:00
compat.c [PATCH] Create compat_sys_migrate_pages 2006-11-03 12:27:59 -08:00
configs.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
cpu.c [PATCH] suspend: don't change cpus_allowed for task initiating the suspend 2006-12-07 08:39:28 -08:00
cpuset.c [PATCH] cpuset: rework cpuset_zone_allowed api 2006-12-13 09:05:49 -08:00
delayacct.c [PATCH] slab: remove kmem_cache_t 2006-12-07 08:39:25 -08:00
dma.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
exec_domain.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
exit.c [PATCH] fdtable: Remove the free_files field 2006-12-10 09:57:22 -08:00
extable.c [PATCH] symbol_put_addr() locks kernel 2006-05-15 11:20:55 -07:00
fork.c [PATCH] fdtable: Remove the free_files field 2006-12-10 09:57:22 -08:00
futex_compat.c [PATCH] __user annotations: futex 2006-10-10 15:37:22 -07:00
futex.c [PATCH] kernel: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:42 -08:00
hrtimer.c [PATCH] posix-timers: Fix clock_nanosleep() doesn't return the remaining time in compatibility mode 2006-09-29 09:18:15 -07:00
itimer.c [PATCH] hrtimers: remove data field 2006-03-26 08:57:03 -08:00
kallsyms.c [PATCH] move kallsyms data to .rodata 2006-12-08 08:28:37 -08:00
Kconfig.hz [PATCH] HZ: 300Hz support 2006-12-07 08:39:36 -08:00
Kconfig.preempt
kexec.c Merge branch 'release' of master.kernel.org:/pub/scm/linux/kernel/git/aegl/linux-2.6 2006-12-07 15:39:22 -08:00
kfifo.c [PATCH] memory ordering in __kfifo primitives 2006-09-29 09:18:13 -07:00
kmod.c [PATCH] rename struct namespace to struct mnt_namespace 2006-12-08 08:28:51 -08:00
kprobes.c [PATCH] kprobes: enable booster on the preemptible kernel 2006-12-07 08:39:38 -08:00
ksysfs.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
kthread.c WorkStruct: Pass the work_struct pointer instead of context data 2006-11-22 14:55:48 +00:00
latency.c [PATCH] severing module.h->sched.h 2006-12-04 02:00:22 -05:00
lockdep_internals.h [PATCH] lockdep: more chains 2006-12-07 08:39:43 -08:00
lockdep_proc.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
lockdep.c [PATCH] lockdep: fix possible races while disabling lock-debugging 2006-12-13 09:05:50 -08:00
Makefile [PATCH] srcu-3: RCU variant permitting read-side blocking 2006-10-04 07:55:30 -07:00
module.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
mutex-debug.c [PATCH] lockdep: show more details about self-test failures 2006-12-07 08:39:43 -08:00
mutex-debug.h [PATCH] lockdep: better lock debugging 2006-07-03 15:27:01 -07:00
mutex.c [PATCH] lockdep: avoid lockdep warning in md 2006-12-08 08:28:39 -08:00
mutex.h [PATCH] lockdep: prove mutex locking correctness 2006-07-03 15:27:04 -07:00
nsproxy.c [PATCH] Revert "[PATCH] identifier to nsproxy" 2006-12-13 09:05:47 -08:00
panic.c [PATCH] x86: Clean up x86 NMI sysctls 2006-09-30 01:47:55 +02:00
params.c [PATCH] module_subsys: initialize earlier 2006-09-29 09:18:08 -07:00
pid.c [PATCH] add child reaper to pid_namespace 2006-12-08 08:28:52 -08:00
posix-cpu-timers.c [PATCH] posix-cpu-timers: prevent signal delivery starvation 2006-10-17 08:18:43 -07:00
posix-timers.c [PATCH] slab: remove kmem_cache_t 2006-12-07 08:39:25 -08:00
printk.c [PATCH] add ignore_loglevel boot option 2006-12-07 08:39:47 -08:00
profile.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
ptrace.c [PATCH] pidspace: is_init() 2006-09-29 09:18:12 -07:00
rcupdate.c [PATCH] rcu: add a prefetch() in rcu_do_batch() 2006-12-07 08:39:40 -08:00
rcutorture.c [PATCH] Add Sparse annotations to SRCU wrapper functions in rcutorture 2006-12-07 08:39:44 -08:00
relay.c [PATCH] Fix numerous kcalloc() calls, convert to kzalloc() 2006-12-13 09:05:52 -08:00
resource.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
rtmutex_common.h [PATCH] pi-futex: futex_lock_pi/futex_unlock_pi support 2006-06-27 17:32:47 -07:00
rtmutex-debug.c Remove all inclusions of <linux/config.h> 2006-10-04 03:38:54 -04:00
rtmutex-debug.h [PATCH] lockdep: better lock debugging 2006-07-03 15:27:01 -07:00
rtmutex-tester.c [PATCH] Add include/linux/freezer.h and move definitions from sched.h 2006-12-07 08:39:27 -08:00
rtmutex.c [PATCH] clean up and remove some extra spinlocks from rtmutex 2006-09-29 09:18:09 -07:00
rtmutex.h [PATCH] lockdep: better lock debugging 2006-07-03 15:27:01 -07:00
rwsem.c [PATCH] lockdep: prove rwsem locking correctness 2006-07-03 15:27:04 -07:00
sched.c [PATCH] lockdep: print irq-trace info on asserts 2006-12-13 09:05:50 -08:00
seccomp.c
signal.c [PATCH] PM: Fix freezing of stopped tasks 2006-12-13 09:05:49 -08:00
softirq.c [PATCH] softirq: remove BUG_ONs which can incorrectly trigger 2006-12-07 08:39:43 -08:00
softlockup.c [PATCH] check return value of cpu_callback 2006-09-29 09:18:14 -07:00
spinlock.c [PATCH] lockdep: spin_lock_irqsave_nested() 2006-11-25 13:28:34 -08:00
srcu.c [PATCH] SRCU: report out-of-memory errors 2006-10-04 07:55:30 -07:00
stacktrace.c [PATCH] lockdep: stacktrace subsystem, core 2006-07-03 15:27:02 -07:00
stop_machine.c [PATCH] stop_machine.c copyright 2006-09-29 09:18:24 -07:00
sys_ni.c [PATCH] Create compat_sys_migrate_pages 2006-11-03 12:27:59 -08:00
sys.c [PATCH] sys_setpgid: eliminate unnecessary do_each_task_pid(PIDTYPE_PGID) 2006-12-08 08:28:52 -08:00
sysctl.c [PATCH] debug: add sysrq_always_enabled boot option 2006-12-13 09:05:50 -08:00
taskstats.c [PATCH] taskstats: cleanup reply assembling 2006-12-07 08:39:34 -08:00
time.c [PATCH] NTP: Move all the NTP related code to ntp.c 2006-10-01 00:39:26 -07:00
timer.c [PATCH] Optimize calc_load() 2006-12-13 09:05:55 -08:00
tsacct.c [PATCH] io-accounting: via taskstats 2006-12-10 09:55:41 -08:00
uid16.c [PATCH] Add more prevent_tail_call() 2006-04-19 16:27:18 -07:00
unwind.c [PATCH] unwinder: move .eh_frame to RODATA 2006-12-07 02:14:19 +01:00
user.c [PATCH] slab: remove kmem_cache_t 2006-12-07 08:39:25 -08:00
utsname.c [PATCH] namespaces: utsname: implement CLONE_NEWUTS flag 2006-10-02 07:57:22 -07:00
wait.c [PATCH] uninline init_waitqueue_head() 2006-07-10 13:24:25 -07:00
workqueue.c [PATCH] WorkStruct: Use direct assignment rather than cmpxchg() 2006-12-09 12:25:08 -08:00