Re: win32 performance - fsync question

From: "Merlin Moncure" <merlin(dot)moncure(at)rcsonline(dot)com>
To: "Christopher Kings-Lynne" <chriskl(at)familyhealth(dot)com(dot)au>
Cc: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Magnus Hagander" <mha(at)sollentuna(dot)net>, <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: win32 performance - fsync question
Date: 2005-02-17 19:14:00
Message-ID: 6EE64EF3AB31D5448D0007DD34EEB3412A7629@Herge.rcsinc.local
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> > WinXP fsync = true 20-28 tps
> > WinXP fsync = false 600 tps
> > Linux fsync = true 800 tps
> > Linux fsync = false 980 tps
>
> Wow, that's terrible on Windows. If there's a solution, it'd be nice
to
> backport it...
>

there is. I just rigged up a test benchmark comparing sync methods. I
ran on 2 boxes, my xp workstation on 10k raptor and a win2k server on
3ware raid 5 (also on 10k raptors).

Workstation:
did 1000 FILE_FLAG_WRITE_THROUGH | FILE_FLAG_NO_BUFFERING writes in
5.729633 seconds
did 1000 FILE_FLAG_WRITE_THROUGH writes in 0.593322 seconds
did 1000 flushfilebuffers writes in 15.898989 seconds

server:
did 1000 FILE_FLAG_WRITE_THROUGH | FILE_FLAG_NO_BUFFERING writes in
16.501076 seconds
did 1000 FILE_FLAG_WRITE_THROUGH writes in 16.104133 seconds
did 1000 flushfilebuffers writes in 18.962439 seconds

server after running super altra secret dskcache '+p' mode:
did 1000 FILE_FLAG_WRITE_THROUGH | FILE_FLAG_NO_BUFFERING writes in
0.256574 seconds
did 1000 FILE_FLAG_WRITE_THROUGH writes in 2.627602 seconds
did 1000 flushfilebuffers writes in 15.290967 seconds

dskcache.exe is required to enable power protect mode (unbypassing raid
conttoller write cache settings) on win2k.

enjoy.
Merlin

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