Re: [PATCH 0/4] per anon_vma lock and turn anon_vma rwsem lock to rwlock_t

Tim Chen
2013-11-05T01:44:07Z

On Mon, 2013-11-04 at 11:59 +0800, Yuanhan Liu wrote:
> On Fri, Nov 01, 2013 at 08:15:13PM -0700, Davidlohr Bueso wrote:
> > On Fri, 2013-11-01 at 18:16 +0800, Yuanhan Liu wrote:
> > > On Fri, Nov 01, 2013 at 09:21:46AM +0100, Ingo Molnar wrote:
> > > >
> > > > * Yuanhan Liu <yuanhan.liu@linux.intel.com> wrote:
> > > >
> > > > > > Btw., another _really_ interesting comparison would be against
> > > > > > the latest rwsem patches. Mind doing such a comparison?
> > > > >
> > > > > Sure. Where can I get it? Are they on some git tree?
> > > >
> > > > I've Cc:-ed Tim Chen who might be able to point you to the latest
> > > > version.
> > > >
> > > > The last on-lkml submission was in this thread:
> > > >
> > > > Subject: [PATCH v8 0/9] rwsem performance optimizations
> > > >
> > >
> > > Thanks.
> > >
> > > I queued bunchs of tests about one hour ago, and already got some
> > > results(If necessary, I can add more data tomorrow when those tests are
> > > finished):
> >
> > What kind of system are you using to run these workloads on?
>
> I queued jobs on 5 testboxes:
> - brickland1: 120 core Ivybridge server
> - lkp-ib03: 48 core Ivybridge server
> - lkp-sb03: 32 core Sandybridge server
> - lkp-nex04: 64 core NHM server
> - lkp-a04: Atom server
> >
> > >
> > >
> > > v3.12-rc7 fe001e3de090e179f95d
> > > ------------------------ ------------------------
> > > -9.3% brickland1/micro/aim7/shared
> > > +4.3% lkp-ib03/micro/aim7/fork_test
> > > +2.2% lkp-ib03/micro/aim7/shared
> > > -2.6% TOTAL aim7.2000.jobs-per-min
> > >
> >
> > Sorry if I'm missing something, but could you elaborate more on what
> > these percentages represent?
>
> v3.12-rc7 fe001e3de090e179f95d
> ------------------------ ------------------------
> -9.3% brickland1/micro/aim7/shared
> ....
> ....
> -2.6% TOTAL aim7.2000.jobs-per-min
>
> The comparation base is v3.12-rc7, and we got 9.3 performance regression
> at commit fe001e3de090e179f95d, which is the head of rwsem performance
> optimizations patch set.

Yunahan, thanks for the data. This I assume is with the entire rwsem
v8 patchset. Any idea of the run variation on the workload?

Tim

>
> "brickland1/micro/aim7/shared" tells the testbox(brickland1) and testcase:
> shared workfile of aim7.
>
> The last line tell what field we are comparing, and it's
> "aim7.2000.jobs-per-min" in this case. 2000 means 2000 users in aim7.
>
> > Are they anon vma rwsem + optimistic
> > spinning patches vs anon vma rwlock?
>
> I tested "[PATCH v8 0/9] rwsem performance optimizations" only.
>
> >
> > Also, I see your running aim7, you might be interested in some of the
> > results I found when trying out Ingo's rwlock conversion patch on a
> > largish 80 core system: https://lkml.org/lkml/2013/9/29/280
>
> Besides aim7, I also tested dbench, hackbench, netperf, pigz. And as you
> can image and see from the data, aim7 benifit most from the anon_vma
> optimization stuff due to high contention of anon_vma lock.
>
> Thanks.
>
> --yliu
>