From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261781AbULBWQA (ORCPT ); Thu, 2 Dec 2004 17:16:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261782AbULBWQA (ORCPT ); Thu, 2 Dec 2004 17:16:00 -0500 Received: from pop.gmx.net ([213.165.64.20]:26772 "HELO mail.gmx.net") by vger.kernel.org with SMTP id S261781AbULBWPn (ORCPT ); Thu, 2 Dec 2004 17:15:43 -0500 X-Authenticated: #4512188 Message-ID: <41AF94B8.8030202@gmx.de> Date: Thu, 02 Dec 2004 23:18:32 +0100 From: "Prakash K. Cheemplavam" User-Agent: Mozilla Thunderbird 0.9 (X11/20041114) X-Accept-Language: de-DE, de, en-us, en MIME-Version: 1.0 To: Andrew Morton CC: Jens Axboe , linux-kernel@vger.kernel.org, nickpiggin@yahoo.com.au Subject: Re: Time sliced CFQ io scheduler References: <20041202130457.GC10458@suse.de> <20041202134801.GE10458@suse.de> <20041202114836.6b2e8d3f.akpm@osdl.org> <20041202195232.GA26695@suse.de> <20041202121938.12a9e5e0.akpm@osdl.org> In-Reply-To: <20041202121938.12a9e5e0.akpm@osdl.org> X-Enigmail-Version: 0.89.0.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig559EAC5132B65144CC4A3F9A" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig559EAC5132B65144CC4A3F9A Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Andrew Morton schrieb: > Jens Axboe wrote: > >>n Thu, Dec 02 2004, Andrew Morton wrote: >> >>>Jens Axboe wrote: >>> >>>>as: >>>>Reader: 27985KiB/sec (max_lat=34msec) >>>>Writer: 64KiB/sec (max_lat=1042msec) >>>> >>>>cfq: >>>>Reader: 12703KiB/sec (max_lat=108msec) >>>>Writer: 9743KiB/sec (max_lat=89msec) > > > Did a quick test here, things seem OK. > > Writer: > > while true > do > dd if=/dev/zero of=foo bs=1M count=1000 conv=notrunc > done > > Reader: > > time cat 1-gig-file > /dev/null > cat x > /dev/null 0.07s user 1.55s system 3% cpu 45.434 total > > `vmstat 1' says: > > > 0 5 1168 3248 472 220972 0 0 28 24896 1249 212 0 7 0 94 > 0 7 1168 3248 492 220952 0 0 28 28056 1284 204 0 5 0 96 > 0 8 1168 3248 500 221012 0 0 28 30632 1255 194 0 5 0 95 > 0 7 1168 2800 508 221344 0 0 16 20432 1183 170 0 3 0 97 > 0 8 1168 3024 484 221164 0 0 15008 12488 1246 460 0 4 0 96 > 1 8 1168 2252 484 221980 0 0 27808 6092 1270 624 0 4 0 96 > 0 8 1168 3248 468 221044 0 0 32420 4596 1290 690 0 4 0 96 > 0 9 1164 2084 456 222212 4 0 28964 1800 1285 596 0 3 0 96 > 1 7 1164 3032 392 221256 0 0 23456 6820 1270 527 0 4 0 96 > 0 9 1164 3200 388 221124 0 0 27040 7868 1269 588 0 3 0 97 > 0 9 1164 2540 384 221808 0 0 21536 4024 1247 540 0 4 0 96 > procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu---- > r b swpd free buff cache si so bi bo in cs us sy id wa > 1 10 1164 2052 392 222276 0 0 33572 5268 1298 745 0 4 0 96 > 0 9 1164 3032 400 221316 0 0 28704 5448 1282 611 0 4 0 97 > I am happy that finally the kernel devs see that there is a problem. In my case (as I mentioned in another thread) the reader is pretty starving while I a writer is active. (esp my email client makes trouble while writing is going on.) This is vmstat using your scripts above (though using cfq2 scheduler): procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 1 3 3080 2528 1256 818976 0 0 6404 101236 1332 929 1 26 0 73 0 3 3080 2768 1252 820104 0 0 2820 32632 1328 1087 1 20 0 79 2 1 3080 6992 1292 814808 0 0 4928 106912 1337 1364 16 29 0 55 0 3 3080 2772 1252 818516 0 0 3076 42176 1357 1351 2 41 0 57 0 3 3080 2644 1256 817548 0 0 3332 110104 1375 873 1 36 0 63 0 3 3080 2592 1248 815928 0 0 2820 76860 1324 894 1 41 0 58 7 3 3080 2208 1248 817176 0 0 3328 134144 1352 1058 2 30 0 68 4 4 3080 2516 1248 817516 0 0 3588 47768 1327 1244 1 19 0 80 0 3 3080 2400 1220 818688 0 0 3844 24760 1312 1251 1 23 0 76 0 3 3080 2656 1196 816468 0 0 3588 132372 1352 1126 1 52 0 47 0 3 3080 2688 1188 815316 0 0 3076 77824 1328 933 1 35 0 64 0 3 3080 2336 1156 816744 0 0 2924 114688 1333 1038 1 25 0 74 0 3 3080 2528 1184 816812 0 0 2508 67736 1340 882 1 12 0 87 0 3 3080 2208 1156 817712 0 0 3592 75624 1326 2289 1 36 0 63 0 3 3080 2664 1156 818240 0 0 5124 15692 1302 992 1 18 0 81 0 3 3080 2580 1160 815832 0 0 4356 155792 1375 1064 1 39 0 60 0 3 3080 2472 1160 817124 0 0 3076 100852 1345 1138 1 23 0 76 2 4 3080 2836 1148 816228 0 0 3336 100412 1352 1379 1 47 0 52 0 4 3080 2708 1144 815964 0 0 3844 48908 1343 871 1 25 0 74 0 3 3080 2748 1152 815984 0 0 3332 71996 1338 843 1 27 0 72 Cheers, Prakash --------------enig559EAC5132B65144CC4A3F9A Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (GNU/Linux) iD8DBQFBr5S8xU2n/+9+t5gRAs1yAKD7LjRcYdRdqoDrWGLjChLhjQXAtgCdECfZ EnYoLKZ+cES1fClTbukAMNE= =yG0A -----END PGP SIGNATURE----- --------------enig559EAC5132B65144CC4A3F9A--