Re: LWLock optimization for multicore Power machines

On 2/21/17 9:54 AM, Bernd Helmle wrote:
> Am Dienstag, den 14.02.2017, 15:53 +0300 schrieb Alexander Korotkov:
>> +1
>> And you could try to use pg_wait_sampling
>> <https://github.com/postgrespro/pg_wait_sampling> to sampling of wait
>> events.
>
> I've tried this with your example from your blog post[1] and got this:
>
> (pgbench scale 1000)
>
> pgbench -Mprepared -S -n -c 100 -j 100 -T 300 -P2 pgbench2
>
> SELECT-only:
>
> SELECT * FROM profile_log ;
> ts | event_type | event | count
> ----------------------------+---------------+---------------+-------
> 2017-02-21 15:21:52.45719 | LWLockNamed | ProcArrayLock | 8
> 2017-02-21 15:22:11.19594 | LWLockTranche | lock_manager | 1
> 2017-02-21 15:22:11.19594 | LWLockNamed | ProcArrayLock | 24
> 2017-02-21 15:22:31.220803 | LWLockNamed | ProcArrayLock | 1
> 2017-02-21 15:23:01.255969 | LWLockNamed | ProcArrayLock | 1
> 2017-02-21 15:23:11.272254 | LWLockNamed | ProcArrayLock | 2
> 2017-02-21 15:23:41.313069 | LWLockNamed | ProcArrayLock | 1
> 2017-02-21 15:24:31.37512 | LWLockNamed | ProcArrayLock | 19
> 2017-02-21 15:24:41.386974 | LWLockNamed | ProcArrayLock | 1
> 2017-02-21 15:26:41.530399 | LWLockNamed | ProcArrayLock | 1
> (10 rows)
>
> writes pgbench runs have far more events logged, see the attached text
> file. Maybe this is of interest...
>
>
> [1] http://akorotkov.github.io/blog/2016/03/25/wait_monitoring_9_6/

This patch applies cleanly at cccbdde. It doesn't break compilation on
amd64 but I can't test on a Power-based machine

Alexander, have you had a chance to look at Bernd's results?

--
-David
david(at)pgmasters(dot)net