linux-kernel - Re: [PATCH 0/6] sched/fair: Compute capacity invariant load/utilization tracking

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 7 Sep 2015 14:42:20 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Morten Rasmussen <morten.rasmussen@....com>
Cc:	mingo@...hat.com, vincent.guittot@...aro.org,
	daniel.lezcano@...aro.org,
	Dietmar Eggemann <Dietmar.Eggemann@....com>,
	yuyang.du@...el.com, mturquette@...libre.com, rjw@...ysocki.net,
	Juri Lelli <Juri.Lelli@....com>, sgurrappadi@...dia.com,
	pang.xunlei@....com.cn, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/6] sched/fair: Compute capacity invariant
 load/utilization tracking

On Mon, Aug 31, 2015 at 11:24:49AM +0200, Peter Zijlstra wrote:

> A quick run here gives:
> 
> IVB-EP (2*20*2):

As noted by someone; that should be 2*10*2, for a total of 40 cpus in
this machine.

> 
> perf stat --null --repeat 10 -- perf bench sched messaging -g 50 -l 5000
> 
> Before:				After:
> 5.484170711 ( +-  0.74% )	5.590001145 ( +-  0.45% )
> 
> Which is an almost 2% slowdown :/
> 
> I've yet to look at what happens.

OK, so it appears this is link order nonsense. When I compared profiles
between the series, the one function that had significant change was
skb_release_data(), which doesn't make much sense.

If I do a 'make clean' in front of each build, I get a repeatable
improvement with this patch set (although how much of that is due to the
patches itself or just because of code movement is as yet undetermined).

I'm of a mind to apply these patches; with two patches on top, which
I'll post shortly.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/