From: | Jignesh Shah <jkshah(at)gmail(dot)com> |
---|---|
To: | Josh Berkus <josh(at)agliodbs(dot)com> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: reducing the overhead of frequent table locks - now, with WIP patch |
Date: | 2011-06-07 03:20:23 |
Message-ID: | BANLkTik0nmy4v-zLs9OSjxXfzkpu+6UFoQ@mail.gmail.com |
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Lists: | pgsql-hackers |
On Mon, Jun 6, 2011 at 2:49 PM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
>
>> That's an improvement of about ~3.5x. According to the vmstat output,
>> when running without the patch, the CPU state was about 40% idle.
>> With the patch, it dropped down to around 6%.
>
> Wow! That's fantastic.
>
> Jignesh, are you in a position to test any of Robert's work using DBT or
> other benchmarks?
>
> --
> Josh Berkus
> PostgreSQL Experts Inc.
> http://pgexperts.com
>
Okay I tried it out with sysbench read scaling test..
Note I had tried that earlier on 9.0
http://jkshah.blogspot.com/2010/11/postgresql-90-simple-select-scaling.html
And on that test I found that doing that test on anything bigger than
4 cores lead to decreased performance ..
Redoing the same test with 100 users on 4 vCPU Virtual Machine with
8GB with 1M rows I get
transactions: 17870082 (59566.46 per sec.)
which is inline with the best number on 9.0.
This test hardly had any idle CPUs.
However where it made a huge impact was doing the same test on my 8
vCPU VM with 8GB RAM I get
transactions: 33274594 (110914.85 per sec.)
which is a whopping 1.8x scaling for 2x scaling (from 4 to 8 vCPU)..
My idle cpu was less than 7% which when taken into consideration that
the "useful" work is line with my expectations is really impressive..
(And plus the last time I did MySQL they were around 95K or so for the
same test).
Also note that in my earlier case 60K was the max irrespective of the
hardware I threw at it.. For this fastlock patch that does not seem to
be the problem anymore :-)
This gain is impressive..
Next step DBT-2..
Regards,
Jignesh
Next step
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