From: Hans Reiser <reiser@namesys.com>
To: Laurent Riffard <laurent.riffard@free.fr>
Cc: reiserfs-list@namesys.com, vs <vs@thebsh.namesys.com>,
Alexander Zarochentcev <zam@namesys.com>
Subject: Re: 2.6.16-rc6-mm2: slow writes on reiser4.
Date: Wed, 22 Mar 2006 11:04:08 -0800 [thread overview]
Message-ID: <44219FA8.2050606@namesys.com> (raw)
In-Reply-To: <44219CC2.3060405@free.fr>
Instead of using sync, could you increase the size of the files you
write so that they are 10x ram size?
I have a suspicion we are slow at sync.... I am not sure why, but I
have seen other data where sync was slow for us, and maybe we need to
optimize that code path.
Hans
Laurent Riffard wrote:
>Le 22.03.2006 08:41, Hans Reiser a écrit :
>
>
>>Laurent Riffard wrote:
>>
>>
>>
>>
>>>Hello,
>>>
>>>Writing big files is very slow on reiser4 now.
>>>
>>>"dd if=/dev/zero of=toto bs=1k count=102400; sync"
>>>
>>>
>>>
>>try bs=4M, and tell me what happens. also try an empty fs, and an fs
>>that is equally full to reiserfs. Note that reiserfs in your test is
>>68% full vs. 90% full for V4. It may be that we need to port some of
>>the block allocation optimizations from V3 to V4 (Jeff's work) to help
>>with 90% full filesystems. Thanks for doing this. Real users always
>>teach me a lot when they test things differently from how I did.
>>
>>Hans
>>
>>
>
>Hello Hans,
>
>Yesterday, I realized that my tests were not fair. So I did some
>further tests trying to have the same situation for 3 different FS
>(reiserfs/ext2/reiser4) and I sent the result to the list, but this
>mail never reached the list. I have resent it.
>
>As per your request, I tried to replay my dd test on my 90% full
>reiser4 FS, using a 4M block size. Here are the results:
>
>---------------------
>
>
>>Desktop$ cd ~/kernel
>>
>>kernel$ rm toto
>>rm: détruire fichier régulier `toto'? o
>>
>>kernel$ df .
>>Sys. de fich. Tail. Occ. Disp. %Occ. Monté sur
>>/dev/hda8 925M 748M 177M 81% /home/laurent/kernel
>>
>>kernel$ grep /dev/hda8 /rpoc/mounts
>>grep: /rpoc/mounts: Aucun fichier ou répertoire de ce type
>>
>>kernel$ grep /dev/hda8 /proc/mounts
>>/dev/hda8 /home/laurent/kernel reiser4 rw,nosuid,nodev,atom_max_size=0x7e0c,atom_max_age=0x249f0,atom_min_size=0x100,atom_max_flushers=0x1,cbk_cache_slots=0x10 0 0
>>
>>kernel$ sync; time dd if=/dev/zero of=toto bs=4M count=25; time sync
>>25+0 enregistrements lus.
>>25+0 enregistrements écrits.
>>0.00user 2.89system 0:17.18elapsed 16%CPU (0avgtext+0avgdata 0maxresident)k
>>0inputs+0outputs (0major+252minor)pagefaults 0swaps
>>0.00user 0.00system 2:19.91elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k
>>0inputs+0outputs (0major+191minor)pagefaults 0swaps
>>
>>kernel$ sync; time dd if=/dev/zero of=toto bs=4M count=25; time sync
>>25+0 enregistrements lus.
>>25+0 enregistrements écrits.
>>0.00user 2.96system 1:16.42elapsed 3%CPU (0avgtext+0avgdata 0maxresident)k
>>0inputs+0outputs (0major+252minor)pagefaults 0swaps
>>0.00user 0.00system 0:08.70elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k
>>0inputs+0outputs (0major+190minor)pagefaults 0swaps
>>
>>
>---------------------
>
>I tried to run an "iostat 10" simultaneously with dd+sync. I
>attached the output. Hope this helps.
>~~
>laurent
>
>
>------------------------------------------------------------------------
>
>Le script a débuté sur mer 22 mar 2006 19:12:56 CET
>Desktop$ cd ~/kernel
>kernel$
>kernel$ sleep 15 && echo SYNC && sync && echo DD && time dd if=/dev/zero of=toto bs=4M count=25 && echo SYNC && time sync && echo END &
>[1] 4657
>kernel$ iostat -t 10 /dev/hda8
>Linux 2.6.16-rc6-mm2 (antares.localdomain) 22.03.2006
>
>Heure: 19:13:32
>avg-cpu: %user %nice %system %iowait %idle
> 5,01 0,02 11,07 4,45 79,46
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 5,34 0,27 217,58 1297 1026592
>
>Heure: 19:13:42
>avg-cpu: %user %nice %system %iowait %idle
> 0,10 0,00 0,20 0,20 99,50
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 0,00 0,00 0,00 0 0
>
>SYNC
>DD
>Heure: 19:13:52
>avg-cpu: %user %nice %system %iowait %idle
> 1,50 0,00 79,32 8,29 10,89
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 20,38 3,20 1202,00 32 12032
>
>Heure: 19:14:02
>avg-cpu: %user %nice %system %iowait %idle
> 2,30 0,00 81,08 16,62 0,00
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 33,53 0,00 1398,20 0 13968
>
>Heure: 19:14:12
>avg-cpu: %user %nice %system %iowait %idle
> 1,90 0,00 88,51 9,59 0,00
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 25,27 0,00 893,51 0 8944
>
>Heure: 19:14:22
>avg-cpu: %user %nice %system %iowait %idle
> 3,19 0,00 85,63 11,18 0,00
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 27,35 0,00 1288,62 0 12912
>
>Heure: 19:14:32
>avg-cpu: %user %nice %system %iowait %idle
> 0,80 0,00 90,01 9,19 0,00
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 25,17 0,00 800,00 0 8008
>
>Heure: 19:14:42
>avg-cpu: %user %nice %system %iowait %idle
> 0,30 0,00 74,93 24,78 0,00
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 54,35 0,00 3138,46 0 31416
>
>Heure: 19:14:52
>avg-cpu: %user %nice %system %iowait %idle
> 0,20 0,00 81,62 18,18 0,00
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 50,75 0,00 1324,28 0 13256
>
>Heure: 19:15:02
>avg-cpu: %user %nice %system %iowait %idle
> 0,60 0,00 71,60 27,80 0,00
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 76,30 0,00 2363,20 0 23632
>
>Heure: 19:15:12
>avg-cpu: %user %nice %system %iowait %idle
> 1,10 0,00 29,77 68,93 0,20
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 123,78 0,00 3275,12 0 32784
>
>25+0 enregistrements lus.
>25+0 enregistrements écrits.
>0.00user 2.94system 1:29.83elapsed 3%CPU (0avgtext+0avgdata 0maxresident)k
>0inputs+0outputs (0major+252minor)pagefaults 0swaps
>SYNC
>Heure: 19:15:22
>avg-cpu: %user %nice %system %iowait %idle
> 2,90 0,00 76,60 19,10 1,40
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 55,10 0,80 1435,20 8 14352
>
>0.00user 0.00system 0:17.41elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k
>0inputs+0outputs (0major+190minor)pagefaults 0swaps
>END
>Heure: 19:15:32
>avg-cpu: %user %nice %system %iowait %idle
> 0,10 0,00 31,73 42,14 26,03
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 94,19 0,00 3402,60 0 33992
>
>Heure: 19:15:42
>avg-cpu: %user %nice %system %iowait %idle
> 0,10 0,00 0,00 0,10 99,80
>
>Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>hda8 0,00 0,00 0,00 0 0
>
>
>^C
>[1]+ Done sleep 15 && echo SYNC && sync && echo DD && time dd if=/dev/zero of=toto bs=4M count=25 && echo SYNC && time sync && echo END
>kernel$ exit
>
>Script complété sur mer 22 mar 2006 19:15:46 CET
>
>
next prev parent reply other threads:[~2006-03-22 19:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-21 21:16 2.6.16-rc6-mm2: slow writes on reiser4 Laurent Riffard
2006-03-22 7:41 ` Hans Reiser
2006-03-22 18:51 ` Laurent Riffard
2006-03-22 19:04 ` Hans Reiser [this message]
2006-03-23 18:44 ` Jindrich Makovicka
2006-03-23 21:32 ` Nate Diller
2006-03-28 20:19 ` Laurent Riffard
2006-03-28 20:34 ` Hans Reiser
2006-03-28 20:56 ` Hans Reiser
2006-03-28 22:49 ` Philippe Gramoullé
2006-03-29 6:16 ` Laurent Riffard
2006-03-29 14:30 ` Philippe Gramoullé
2006-04-01 23:15 ` Pierre Etchemaïté
2006-03-22 17:48 ` Laurent Riffard
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=44219FA8.2050606@namesys.com \
--to=reiser@namesys.com \
--cc=laurent.riffard@free.fr \
--cc=reiserfs-list@namesys.com \
--cc=vs@thebsh.namesys.com \
--cc=zam@namesys.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.