Re: Should we cacheline align PGXACT?

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.

>
> *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 <(502)%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.
>

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