Re: Should we cacheline align PGXACT?

On Tue, Feb 28, 2017 at 11:44 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:

> On 28 February 2017 at 11:34, Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com>
> wrote:
>
>
>> So, Here are the pgbench results I got with '
>> *reduce_pgxact_access_AtEOXact.v2.patch*' on a read-write workload.
>>
>
> Thanks for performing a test.
>
> I see a low yet noticeable performance gain across the board on that
> workload.
>
> That is quite surprising to see a gain on that workload. The main workload
> we have been discussing was the full read-only test (-S). For that case the
> effect should be much more noticeable based upon Andres' earlier comments.
>
> Would it be possible to re-run the test using only the -S workload? Thanks
> very much.
>

Okay, I already had the results for read-oly workload but just forgot to
share it along with the results for read-write test. Here are the results
for read-only
test,

CLIENT COUNT TPS (HEAD) TPS (PATCH) % IMPROVEMENT
4 26322 31259 18.75617354
8 63499 69472 9.406447346
16 181155 186534 2.96928045
32 333504 337533 1.208081462
64 350341 353747 0.9721956608
72 366339 373898 2.063389374
128 443381 478562 7.934710779
180 299875 334118 11.41909129
196 269194 275525 2.351835479
256 220027 235995 7.257291151

The pgbench settings and non-default params are,

pgbench -i -s 300 postgres
pgbench -M prepared -c $thread -j $thread -T $time_for_reading -S postgres

where, time_for_reading = 10mins

*non default param:*
shared_buffers=8GB
max_connections=300

--
With Regards,
Ashutosh Sharma
EnterpriseDB:http://www.enterprisedb.com

>
>> *pgbench settings:*
>> pgbench -i -s 300 postgres
>> pgbench -M prepared -c $thread -j $thread -T $time_for_reading postgres
>>
>> where, time_for_reading = 30mins
>>
>> *non default GUC param*
>> shared_buffers=8GB
>> max_connections=300
>>
>> pg_wal is located in SSD.
>>
>> CLIENT COUNT TPS (HEAD) TPS (PATCH) % IMPROVEMENT
>> 4 2588 2601 0.5023183926 <%28502%29%20318-3926>
>> 8 5094 5098 0.0785237534
>> 16 10294 10307 0.1262871576
>> 32 19779 19815 0.182011224
>> 64 27908 28346 1.569442454
>> 72 27823 28416 2.131330194
>> 128 28455 28618 0.5728342998
>> 180 26739 26879 0.5235797898
>> 196 27820 27963 0.5140186916
>> 256 28763 28969 0.7161978931
>>
>> Also, Excel sheet (results-readwrite-300-SF.xlsx) containing the results
>> for all the 3 runs is attached.
>>
>
>
>
> --
> Simon Riggs http://www.2ndQuadrant.com/
> <http://www.2ndquadrant.com/>
> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>