From: Paul Turner <pjt@google.com>
To: Jason Baron <jbaron@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Bharata B Rao <bharata@linux.vnet.ibm.com>,
Dhaval Giani <dhaval.giani@gmail.com>,
Balbir Singh <bsingharora@gmail.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
Srivatsa Vaddagiri <vatsa@in.ibm.com>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
Ingo Molnar <mingo@elte.hu>, Pavel Emelyanov <xemul@openvz.org>,
rth@redhat.com
Subject: Re: [RFT][patch 17/18] sched: use jump labels to reduce overhead when bandwidth control is inactive
Date: Thu, 4 Aug 2011 20:55:08 -0700 [thread overview]
Message-ID: <CAPM31RKQyKukoNXLeiLkQ0fdOiDizZRtviR=J+93PhJD9r-SkQ@mail.gmail.com> (raw)
In-Reply-To: <20110727215816.GA2515@redhat.com>
> --- 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
>
>
>
next prev parent reply other threads:[~2011-08-05 3:55 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-22 0:32 Jason Baron
2011-07-22 0:57 ` Paul Turner
2011-07-22 1:17 ` [RFT][patch 17/18] sched: use jump labels to reduce overhead when bandwidth control is inactive Jason Baron
2011-07-22 1:38 ` Paul Turner
2011-07-27 21:58 ` Jason Baron
2011-08-05 3:53 ` Paul Turner
2011-08-05 7:21 ` Peter Zijlstra
2011-08-05 3:55 ` Paul Turner [this message]
2011-08-05 18:28 ` Jason Baron
2011-08-05 8:30 ` Peter Zijlstra
2011-08-05 15:11 ` Richard Henderson
2011-08-05 15:14 ` Peter Zijlstra
2011-08-05 15:24 ` Jason Baron
-- strict thread matches above, loose matches on Subject: below --
2011-07-21 16:43 [patch 00/18] CFS Bandwidth Control v7.2 Paul Turner
2011-07-21 16:43 ` [RFT][patch 17/18] sched: use jump labels to reduce overhead when bandwidth control is inactive Paul Turner
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