Ingo Molnar f20bf61256 time: introduce xtime_seconds ... improve performance of sys_time(). sys_time() returns time in seconds, but it does so by calling do_gettimeofday() and then returning the tv_sec portion of the GTOD time. But the data structure "xtime", which is updated by every timer/scheduler tick, already offers HZ granularity time. the patch improves the sysbench oltp macrobenchmark by 4-5% on an AMD dual-core system: v2.6.23: #threads 1: transactions: 4073 (407.23 per sec.) 2: transactions: 8530 (852.81 per sec.) 3: transactions: 8321 (831.88 per sec.) 4: transactions: 8407 (840.58 per sec.) 5: transactions: 8070 (806.74 per sec.) v2.6.23 + sys_time-speedup.patch: 1: transactions: 4281 (428.09 per sec.) 2: transactions: 8910 (890.85 per sec.) 3: transactions: 8659 (865.79 per sec.) 4: transactions: 8676 (867.34 per sec.) 5: transactions: 8532 (852.91 per sec.) and by 4-5% on an Intel dual-core system too: 2.6.23: 1: transactions: 4560 (455.94 per sec.) 2: transactions: 10094 (1009.30 per sec.) 3: transactions: 9755 (975.36 per sec.) 4: transactions: 9859 (985.78 per sec.) 5: transactions: 9701 (969.72 per sec.) 2.6.23 + sys_time-speedup.patch: 1: transactions: 4779 (477.84 per sec.) 2: transactions: 10103 (1010.14 per sec.) 3: transactions: 10141 (1013.93 per sec.) 4: transactions: 10371 (1036.89 per sec.) 5: transactions: 10178 (1017.50 per sec.) (the more CPUs the system has, the more speedup this patch gives for this particular workload.) Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2007-10-16 10:01:50 -07:00
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irq
power
time
.gitignore
acct.c
audit.c
audit.h
auditfilter.c
auditsc.c
capability.c
compat.c
configs.c
cpu.c
cpuset.c
delayacct.c
die_notifier.c
dma.c
exec_domain.c
exit.c
extable.c
fork.c
futex_compat.c
futex.c
hrtimer.c
itimer.c
kallsyms.c
Kconfig.hz
Kconfig.preempt
kexec.c
kfifo.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latency.c
lockdep_internals.h
lockdep_proc.c
lockdep.c
Makefile
module.c
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
nsproxy.c
panic.c
params.c
pid.c
posix-cpu-timers.c
posix-timers.c
printk.c
profile.c
ptrace.c
rcupdate.c
rcutorture.c
relay.c
resource.c
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
sched_debug.c
sched_fair.c
sched_idletask.c
sched_rt.c
sched_stats.h
sched.c
seccomp.c
signal.c
softirq.c
softlockup.c
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c
sys.c
sysctl.c
taskstats.c
time.c
timer.c
tsacct.c
uid16.c
user_namespace.c
user.c
utsname_sysctl.c
utsname.c
wait.c
workqueue.c