Re: Wait free LW_SHARED acquisition - v0.9

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От Amit Kapila
Тема Re: Wait free LW_SHARED acquisition - v0.9
Дата
Msg-id CAA4eK1L-cRejyfBNwY-i9RCz1ayuuFYuTe_u5DmmPmV+QXO1zQ@mail.gmail.com
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Ответ на Re: Wait free LW_SHARED acquisition - v0.9  (Amit Kapila <amit.kapila16@gmail.com>)
Ответы Re: Wait free LW_SHARED acquisition - v0.9
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On Sat, Oct 11, 2014 at 7:02 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Sat, Oct 11, 2014 at 6:40 PM, Andres Freund <andres@2ndquadrant.com> wrote:
> > On 2014-10-11 07:26:57 +0530, Amit Kapila wrote:
> > > On Sat, Oct 11, 2014 at 7:00 AM, Andres Freund <andres@2ndquadrant.com>
> > > > And since
> > > > your general performance numbers are a fair bit lower than what I see
> > > > with, hopefully, the same code on the same machine...
> > >
> > > You have reported numbers at 1000 scale factor and mine were
> > > at 3000 scale factor, so I think the difference is expected.
> >
> > The numbers for 3000 show pretty much the same:
> >
> > SCALE           128             160             175
> > HEAD            352113          339005          336491
> > LW_SHARED       365874          347931          342528
> >
> > Hm. I wonder if you're using pgbench without -M prepared?
>
> No, I use below statement:
> ./pgbench -c 128 -j 128 -T 300 -S -M prepared postgres
>
> > That'd about
> > explain the difference.
>
> Here I think first thing to clarify is why the numbers on HEAD are
> different?

I have taken the latest code and recreated the database and tried
again on power-7 m/c (hydra) and below is the result:

Result with -M prepared:
Duration of each individual run - 5 mins 

HEAD – commit 494affb

Shared_buffers=8GB; Scale Factor = 3000

Client Count/No. Of Runs (tps)128160
Run-1258385239908
Run-2257835238624
Run-3255967237905


Result without -M prepared:
Duration of each individual run - 5 mins


HEAD – commit 494affb

Shared_buffers=8GB; Scale Factor = 3000

Client Count/No. Of Runs (tps)128160
Run-1228747220961
Run-2229817214464
Run-3227386216619


I am not sure why we are seeing difference even though running
on same m/c with same configuration.  I think there is some
difference in the way we are running tests, if you don't mind
could you please share the exact steps and non-default postgresql.conf
settings with me.  The below list of things could be useful for
me to reproduce the numbers you are seeing:

a. build steps (any script you are using)
b. non-default postgresql.conf settings
c. Exact pgbench statements used


With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com

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