> Well, off the top of my head I would of course be sure to build > Postgres to take advantage of this: > > * Vectorization of the algorithm requires 32bit x 32bit -> 32bit integer > * multiplication instruction. As of 2013 the corresponding instruction is > * available on x86 SSE4.1 extensions (pmulld) and ARM NEON (vmul.i32). > * Vectorization requires a compiler to do the vectorization for us. For recent > * GCC versions the flags -msse4.1 -funroll-loops -ftree-vectorize are enough > * to achieve vectorization. > > Unfortunately I have no idea what packagers are currently doing about > this. Could you please enlighten me, Devrim? No problem. We will install PostgreSQL from source code anyway. I tried in my local environment, PostgreSQL compiles fine with the addional arguments you gave me and passed regression test (of course pg_regress.c is modified to add initdb -k flag). > It also occurs to me that pgbench will be pretty unsympathetic to > checksums as compared to a non-checksummed baseline here, because of > course as always it uses a uniform distribution, and that's going to > literally maximize the amount of verification that must occur. Maybe > that's something you're interested in, because you want to > characterize the worst case. If the average case is more interesting, > you could try applying this patch: > > https://commitfest.postgresql.org/action/patch_view?id=1240 > > I don't know if the patch is any good, having not looked at the code, > but surely as the original author of pgbench you are eminently > qualified to judge this. I think that in general I prefer a uniform > distribution, because most often I look to pgbench to satisfy myself > that certain types of regressions have not occurred. That's quite a > different thing to a representative workload, obviously. Ok, I will look into this when I have enough time. -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
