Re: Some performance testing?

From a measurement I took back when we did the upgrade:

performance with 2.6: (pgbench, size 100, 32 clients)

48 651 transactions per second (read only)
6 504 transactions per second (read-write)

performance with 3.18 (pgbench, size 100, 32 clients)

129 303 transactions per second (read only)
16 895 transactions (read-write)

So that looks like 2.6x improvement to reads and writes. That was an 8 core xeon server with H710P and 4x crucial M550 SSDs in RAID, pg9.3.

Graeme Bell

On 09 Apr 2015, at 12:39, Przemysław Deć <przemyslaw(dot)dec(at)linuxpolska(dot)pl> wrote:

> Can you say how much faster it was?
>
> Przemek Deć
>
> 2015-04-09 11:04 GMT+02:00 Graeme B. Bell <grb(at)skogoglandskap(dot)no>:
> >
> > Josh, there seems to be an inconsistency in your blog. You say 3.10.X is
> > safe, but the graph you show with the poor performance seems to be from
> > 3.13.X which as I understand it is a later kernel. Can you clarify which
> > 3.X kernels are good to use and which are not?
>
> Sorry to cut in -
>
> So far we've found kernel 3.18 to be excellent for postgres 9.3 performance (pgbench + our own queries run much faster than with the 2.6.32-504 centos 6 kernel, and we haven't encountered random stalls or slowness).
>
> We use elrepo to get prebuilt rpms of the latest mainline stable kernel (kernel-ml).
>
> http://elrepo.org/tiki/kernel-ml
>
> Graeme Bell
>
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