Messages in this thread | | | From | Paul Turner <> | Date | Thu, 4 Aug 2011 20:55:08 -0700 | Subject | Re: [RFT][patch 17/18] sched: use jump labels to reduce overhead when bandwidth control is inactive |
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> --- a/kernel/Makefile > +++ b/kernel/Makefile > @@ -10,7 +10,7 @@ obj-y = sched.o fork.o exec_domain.o panic.o printk.o \ > kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \ > hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \ > notifier.o ksysfs.o pm_qos_params.o sched_clock.o cred.o \ > - async.o range.o jump_label.o > + async.o range.o > obj-y += groups.o > > ifdef CONFIG_FUNCTION_TRACER > @@ -107,6 +107,7 @@ obj-$(CONFIG_PERF_EVENTS) += events/ > obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o > obj-$(CONFIG_PADATA) += padata.o > obj-$(CONFIG_CRASH_DUMP) += crash_dump.o > +obj-$(CONFIG_JUMP_LABEL) += jump_label.o > > ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y) > # According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is >
Tested-by: Paul Turner <pjt@google.com>
Let me know if you need any result tables for the actual commit msg. Same goes for making CONFIG_JUMP_LABEL equivalent to default in CC_HAS_ASM_GOTO case (at least on x86 anyway).
> > I've tested the patch using a single 'static_branch()' in the getppid() path, > and basically running tight loops of calls to getppid(). Before, the > patch, I was seeing results similar to what you reported, after the > patch, things improved for all metrics. Here are my results for the > branch disabled case: > > With jump labels turned on (CONFIG_JUMP_LABEL), branch disabled: > > Performance counter stats for 'bash -c /tmp/timing;true' (50 runs): > > 3,969,510,217 instructions # 0.864 IPC ( +-0.000% ) > 4,592,334,954 cycles ( +- 0.046% ) > 751,634,470 branches ( +- 0.000% ) > > 1.722635797 seconds time elapsed ( +- 0.046% ) > > Jump labels turned off (CONFIG_JUMP_LABEL not set), branch disabled: > > Performance counter stats for 'bash -c /tmp/timing;true' (50 runs): > > 4,009,611,846 instructions # 0.867 IPC ( +-0.000% ) > 4,622,210,580 cycles ( +- 0.012% ) > 771,662,904 branches ( +- 0.000% ) > > 1.734341454 seconds time elapsed ( +- 0.022% ) > > > So all of the measured metrics improved in the jump labels case b/w > 0.5% - 2.5%. > > I'm curious to see what you find with this patch. > > Thanks, > > -Jason > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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