Re: LWLock optimization for multicore Power machines

Hi Alexander,

On 3/16/17 1:35 PM, David Steele wrote:
> 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?

I'm marking this submission "Waiting for Author" as your input seems to
be required.

This thread has been idle for a week. Please respond and/or post a new
patch by 2017-03-28 00:00 AoE (UTC-12) or this submission will be marked
"Returned with Feedback".

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