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

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

On Mon, Nov 04, 2013 at 05:44:00PM -0800, Tim Chen wrote:
> 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.

Yes, it is; 9 patches in total.

> Any idea of the run variation on the workload?

Your concern is right. The variation is quite big on the brickland1/micro/aim7/shared
testcase.

   * - v3.12-rc7
   O - fe001e3de090e179f95d

                 brickland1/micro/aim7/shared: aim7.2000.jobs-per-min

   320000 ++----------------------------------------------------------------+
          |                                                                 |
   310000 ++                              .*.........                       |
          |                           ....           .......                |
   300000 ++                      ....                      .......         |
          |                    ...                                 ......   |
   290000 ++               ....                                          ...|
          |            ....                                                 *
   280000 ++        ...                                                     |
          |     ....                                                        |
   270000 ++....                                                            |
          *.                                                                O
   260000 O+                                                                |
          |                                O                                |
   250000 ++----------------------------------------------------------------+


	--yliu
> > 
> > "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
> > 
>