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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
..
irq request_irq: fix DEBUG_SHIRQ handling 2007-08-31 01:42:23 -07:00
power hibernation doesn't even build on frv - tons of helpers are missing 2007-09-26 09:22:04 -07:00
time time: introduce xtime_seconds 2007-10-16 10:01:50 -07:00
.gitignore
acct.c Cleanup non-arch xtime uses, use get_seconds() or current_kernel_time(). 2007-07-25 10:09:20 -07:00
audit.c [NET]: make netlink user -> kernel interface synchronious 2007-10-10 21:15:29 -07:00
audit.h Audit: add TTY input auditing 2007-07-16 09:05:47 -07:00
auditfilter.c [PATCH] allow audit filtering on bit & operations 2007-07-22 09:57:02 -04:00
auditsc.c SUNRPC: Convert rpc_pipefs to use the generic filesystem notification hooks 2007-10-09 17:15:26 -04:00
capability.c [PATCH] pid: replace do/while_each_task_pid with do/while_each_pid_task 2007-02-12 09:48:32 -08:00
compat.c signal/timer/event: timerfd compat code 2007-05-11 08:29:36 -07:00
configs.c use simple_read_from_buffer in kernel/ 2007-05-09 12:30:49 -07:00
cpu.c PM: Fix dependencies of CONFIG_SUSPEND and CONFIG_HIBERNATION 2007-08-31 01:42:22 -07:00
cpuset.c cpuset: remove sched domain hooks from cpusets 2007-10-16 09:43:09 -07:00
delayacct.c sched: clean up schedstats, cnt -> count 2007-10-15 17:00:12 +02:00
die_notifier.c move die notifier handling to common code 2007-05-08 11:15:04 -07:00
dma.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
exec_domain.c
exit.c sched: guest CPU accounting: add guest-CPU /proc/<pid>/stat fields 2007-10-15 17:00:19 +02:00
extable.c
fork.c sched: guest CPU accounting: add guest-CPU /proc/<pid>/stat fields 2007-10-15 17:00:19 +02:00
futex_compat.c robust futex thread exit race 2007-10-01 07:52:23 -07:00
futex.c robust futex thread exit race 2007-10-01 07:52:23 -07:00
hrtimer.c [KTIME]: Introduce ktime_sub_ns and ktime_sub_us 2007-10-10 16:48:12 -07:00
itimer.c The scheduled -EINVAL for invalid timevals in setitimer 2007-05-08 11:15:13 -07:00
kallsyms.c kallsyms: make KSYM_NAME_LEN include space for trailing '\0' 2007-07-17 10:23:03 -07:00
Kconfig.hz [PATCH] HZ: 300Hz support 2006-12-07 08:39:36 -08:00
Kconfig.preempt [PATCH] sched: arch preempt notifier mechanism 2007-07-26 13:40:43 +02:00
kexec.c kdump/kexec: calculate note size at compile time 2007-05-08 11:15:07 -07:00
kfifo.c is_power_of_2: kernel/kfifo.c 2007-07-16 09:05:50 -07:00
kmod.c Restore call_usermodehelper_pipe() behaviour 2007-09-11 17:21:20 -07:00
kprobes.c kprobes: support kretprobe blacklist 2007-10-16 09:43:10 -07:00
ksysfs.c sched: group scheduling, sysfs tunables 2007-10-15 17:00:14 +02:00
kthread.c kthread: silence bogus section mismatch warning 2007-07-31 15:39:42 -07:00
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 lockdep: Avoid /proc/lockdep & lock_stat infinite output 2007-10-11 22:11:11 +02:00
lockdep.c lockdep: syscall exit check 2007-10-11 22:11:12 +02:00
Makefile user namespace: add the framework 2007-07-16 09:05:47 -07:00
module.c Fix Off-by-one in /sys/module/*/refcnt 2007-08-22 14:35:35 -07:00
mutex-debug.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
mutex-debug.h
mutex.c lockdep: fixup mutex annotations 2007-10-11 22:11:12 +02:00
mutex.h
nsproxy.c [NET]: Add network namespace clone & unshare support. 2007-10-10 16:52:46 -07:00
panic.c Report that kernel is tainted if there was an OOPS 2007-07-17 10:23:02 -07:00
params.c modules: better error messages when modules fail to load due to a sysfs problem. 2007-07-30 14:25:23 -07:00
pid.c namespace: ensure clone_flags are always stored in an unsigned long 2007-07-16 09:05:48 -07:00
posix-cpu-timers.c sched: make posix-cpu-timers use CFS's accounting information 2007-07-09 18:51:58 +02:00
posix-timers.c more low-hanging fruits - kernel, fs, lib signedness 2007-10-14 12:41:52 -07:00
printk.c slow down printk during boot 2007-10-16 09:42:49 -07:00
profile.c Memoryless nodes: Allow profiling data to fall back to other nodes 2007-10-16 09:42:58 -07:00
ptrace.c m32r: convert to generic sys_ptrace 2007-10-16 09:43:04 -07:00
rcupdate.c lockdep: annotate rcu_read_{,un}lock{,_bh} 2007-10-11 22:11:12 +02:00
rcutorture.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
relay.c Fix a use after free bug in kernel->userspace relay file support 2007-07-31 15:39:42 -07:00
resource.c memory unplug: memory hotplug cleanup 2007-10-16 09:43:01 -07:00
rtmutex_common.h FUTEX: Tidy up the code 2007-07-16 09:05:49 -07:00
rtmutex-debug.c FUTEX: Tidy up the code 2007-07-16 09:05:49 -07:00
rtmutex-debug.h
rtmutex-tester.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
rtmutex.c FUTEX: Tidy up the code 2007-07-16 09:05:49 -07:00
rtmutex.h
rwsem.c lockstat: hook into spinlock_t, rwlock_t, rwsem and mutex 2007-07-19 10:04:49 -07:00
sched_debug.c Make scheduler debug file operations const 2007-10-15 17:00:19 +02:00
sched_fair.c sched: reintroduce cache-hot affinity 2007-10-15 17:00:18 +02:00
sched_idletask.c sched: mark scheduling classes as const 2007-10-15 17:00:12 +02:00
sched_rt.c sched: tidy up SCHED_RR 2007-10-15 17:00:13 +02:00
sched_stats.h sched: clean up schedstats, cnt -> count 2007-10-15 17:00:12 +02:00
sched.c cpuset: remove sched domain hooks from cpusets 2007-10-16 09:43:09 -07:00
seccomp.c make seccomp zerocost in schedule 2007-07-16 09:05:50 -07:00
signal.c fix bogus reporting of signals by audit 2007-10-07 16:28:43 -07:00
softirq.c [KERNEL]: Unexport raise_softirq_irqoff 2007-10-10 16:49:18 -07:00
softlockup.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
spinlock.c lockstat: hook into spinlock_t, rwlock_t, rwsem and mutex 2007-07-19 10:04:49 -07:00
srcu.c [PATCH] SRCU: report out-of-memory errors 2006-10-04 07:55:30 -07:00
stacktrace.c
stop_machine.c Fix stop_machine_run problem with naughty real time process 2007-07-16 09:05:41 -07:00
sys_ni.c diskquota: 32bit quota tools on 64bit architectures 2007-07-16 09:05:48 -07:00
sys.c Fix SMP poweroff hangs 2007-10-01 07:52:23 -07:00
sysctl.c hugetlb: Add hugetlb_dynamic_pool sysctl 2007-10-16 09:43:02 -07:00
taskstats.c taskstats: add context-switch counters 2007-07-16 09:05:46 -07:00
time.c time: introduce xtime_seconds 2007-10-16 10:01:50 -07:00
timer.c Pull ia64-clocksource into release branch 2007-07-20 11:26:47 -07:00
tsacct.c Cleanup non-arch xtime uses, use get_seconds() or current_kernel_time(). 2007-07-25 10:09:20 -07:00
uid16.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
user_namespace.c Fix user namespace exiting OOPs 2007-09-19 11:24:18 -07:00
user.c sched: generate uevents for user creation/destruction 2007-10-15 17:00:18 +02:00
utsname_sysctl.c remove CONFIG_UTS_NS and CONFIG_IPC_NS 2007-07-16 09:05:47 -07:00
utsname.c Fix UTS corruption during clone(CLONE_NEWUTS) 2007-09-19 11:24:17 -07:00
wait.c Fix occurrences of "the the " 2007-05-09 08:57:56 +02:00
workqueue.c fix bogus hotplug cpu warning 2007-08-27 10:27:48 -07:00