From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 18 Sep 2001 00:06:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 18 Sep 2001 00:05:52 -0400 Received: from paloma16.e0k.nbg-hannover.de ([62.159.219.16]:38602 "HELO paloma16.e0k.nbg-hannover.de") by vger.kernel.org with SMTP id ; Tue, 18 Sep 2001 00:05:44 -0400 From: Dieter =?iso-8859-1?q?N=FCtzel?= Organization: DN To: Robert Love , Chris Mason Subject: Re: Feedback on preemptible kernel patch Date: Tue, 18 Sep 2001 06:06:06 +0200 X-Mailer: KMail [version 1.3.1] Cc: Linux Kernel List , ReiserFS List In-Reply-To: <200109140302.f8E32LG13400@zero.tech9.net> <200109150444.f8F4iEG19063@zero.tech9.net> <1000530869.32365.21.camel@phantasy> In-Reply-To: <1000530869.32365.21.camel@phantasy> MIME-Version: 1.0 Content-Type: Multipart/Mixed; boundary="------------Boundary-00=_6EBUCA9ETT9KDWGHCWC8" Message-Id: <20010918040550Z273827-761+10122@vger.kernel.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --------------Boundary-00=_6EBUCA9ETT9KDWGHCWC8 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Am Samstag, 15. September 2001 07:14 schrieb Robert Love: > On Sat, 2001-09-15 at 00:25, Dieter Nützel wrote: > > > > > ReiserFS may be another problem. > > > > > > > > Can't wait for that. > > > > Most wanted, now. > > I am working on it, but I am unfamilar with it all. > > Are you seeing any specific problems, now? With the latest preemption > patch on 2.4.10-pre9, do you crash? oops? No, nothing with 2.4.10-pre9 + patch-rml-2.4.10-pre9-preempt-kernel-1 and your MMX/3Dnow! fix. 2.4.10-pre10 + patch-rml-2.4.10-pre10-preempt-kernel-1 seems to be a winner! See my results below. > The only outstanding issue now is ReiserFS issues. Yes, but no crash or oops for me. "Only" some "stalls" during MPEG/Ogg-Vorbis playback (2-5 sec) :-( > > It seems to be that kswap put some additional "load" on the disk from > > time to time. Or is it the ReiserFS thing, again? > > I don't think its related to ReiserFS. I think you are right. > What sort of activity are you seeing? How often? How do you know its > kswapd? I saw it with "top" at the first line (but only some few percent). It was during untarring some mid-sized archives (DRI) which took normally ~10 sec, but with kswap and 2.4.9-pre9+your patches ~30 sec. Even "sync" needed some additional seconds. Are there some reschedule/context switch (kernel lock release) statements missing in ReiserFS? Is this possible? Chris? > I am glad the patch fixed it, the final version of that is going into > the next preemption patch. Stay tuned. I am very happy with patch-rml-2.4.10-pre10-preempt-kernel-1. > These results are pretty good. Throughput seems down 2-3% in many > cases, although latency is greatly improved. Look at those latency > changes! From thousands of ms to hundreds of us in bonnie. Wow. So look at my latest numbers. This time preempt only, sorry. If you need 2.4.10-pre10 only, too please ask. > Even if you don't care about latency (I'm not an audio person or > anything), these changes should be worth it. I do. Or better, one of my friend's father will do some digital video editing with Linux:-) > > Deleting with ReiserFS and the preempt kernel is GREAT! > > Good. I/O latency should be great now, with little change in > throughput... It is. > > But I get some hiccup during noatun (mp3, ogg, etc. player for KDE-2.2) > > or plaympeg together with dbench (16, 32). ReiserFS needs some preemption > > fixes, too? > > You may still get some small hiccups ( < 1 second?) even with the > preemption patch, as kernel locks prevent preemption (the patch can't > guarentee low latency, just preemption outside of the locks). Sadly 2-5 seconds at the beginning of dbench and during bonnie++ block operations (huge IO pressure, ~20% system, 3-5% user, 116308 kilobytes paged out). > However, how bad was the hiccups with preemption disabled? I have heard > reports where it is 3-5sec at times. Yes, nearly the same. > As the kernel becomes more scalable (finer-grain locking), preemption > will improve. Past that, perhaps during 2.5, we can work on some other > things to improve preemption. Is this a ReiserFS only problem? Uninteruptable IO? > > I've attached two small compressed bonnie++ HTML files. > > These were neat, thanks. One more. > Thank you for your feedback and support. Stay current with the kernel > and the preemption patches, I will. > and I will try to figure the ReiserFS crashes out. No crashes for me only the stalls. Regards, Dieter 2.4.10-pre10 + patch-rml-2.4.10-pre10-preempt-kernel-1 dbench-1.1 32 Throughput 26.2881 MB/sec (NB=32.8601 MB/sec 262.881 MBit/sec) 14.320u 54.140s 2:41.70 42.3% 0+0k 0+0io 911pf+0w load: 2931 Throughput 27.3814 MB/sec (NB=34.2267 MB/sec 273.814 MBit/sec) 14.040u 55.920s 2:35.29 45.0% 0+0k 0+0io 911pf+0w load: 2955 dbench 16 Throughput 32.9183 MB/sec (NB=41.1479 MB/sec 329.183 MBit/sec) 6.790u 26.580s 1:05.17 51.2% 0+0k 0+0io 511pf+0w dbench 8 Throughput 34.8936 MB/sec (NB=43.617 MB/sec 348.936 MBit/sec) 3.300u 12.760s 0:31.27 51.3% 0+0k 0+0io 311pf+0w dbench 4 Throughput 38.3568 MB/sec (NB=47.946 MB/sec 383.568 MBit/sec) 1.770u 6.160s 0:14.77 53.6% 0+0k 0+0io 211pf+0w SunWave1>sync dbench 2 Throughput 53.3066 MB/sec (NB=66.6333 MB/sec 533.066 MBit/sec) 0.940u 2.970s 0:05.95 65.7% 0+0k 0+0io 161pf+0w dbench 1 Throughput 24.0354 MB/sec (NB=30.0442 MB/sec 240.354 MBit/sec) 0.470u 1.460s 0:06.49 29.7% 0+0k 0+0io 136pf+0w Throughput 39.1102 MB/sec (NB=48.8878 MB/sec 391.102 MBit/sec) 0.400u 1.530s 0:04.38 44.0% 0+0k 0+0io 136pf+0w Throughput 44.6889 MB/sec (NB=55.8611 MB/sec 446.889 MBit/sec) 0.500u 1.430s 0:03.96 48.7% 0+0k 0+0io 136pf+0w Version 1.92a ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP SunWave1 1248M 107 96 16513 21 9004 9 163 98 27844 18 256.9 3 Latency 115ms 2872ms 1743ms 121ms 64671us 3273ms Version 1.92a ------Sequential Create------ --------Random Create-------- SunWave1 -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 6029 69 +++++ +++ 13252 94 6762 82 +++++ +++ 11342 94 Latency 338ms 16041us 16309us 24248us 367us 17045us load: 292 --------------Boundary-00=_6EBUCA9ETT9KDWGHCWC8 Content-Type: application/x-bzip2; name="2.4.10-pre10.html.bz2" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="2.4.10-pre10.html.bz2" QlpoOTFBWSZTWbFIYjYAAXbfgHAQegv//z/v37A/7//6UAOr27lyCA6tsEkkIaaQ009TbU1PUbSe oaaADQ0A0eoAaDTUmJoyKeUBkZANMRgRk0yaYQBoYSJBBE1HtI9UHqeoNAGh4oYTR6EAAHNMjIZM ENGEwRpo0YgaZMjAAEEVEyAlN4ptTTTKZGQHqDQPUND1ADQZGK2MlQjAsMnnjqrje/cLTCSlBWDP naGOAt2ucAM/Wj3AgUAcs/RIecxgBIwUDnSTZ6B5hyWcFZqAjj5DyOxYSbULQHdR+KVpgAGYTtA8 aZoEQgSAYhcAvcKZp3wvJ2Pqzkx7GBLIMkl2Mkkj0ZEsmC42DC6fpz59lMDXBPRv9nKlPXsiQHbP JZpYyM0Fo2Mlb4iRCWZkOJEAkASCAhFICg3IKFV00ATMVRMzwdFT20UvbSuV7ROx6mtYGselM65S FFinmVYkffKWSTi6x3UrbK510MLXFl3CvUHB9pBslw6SOqe7KNh4AYiR/0q6MK4pQB1QLiUdhEOe kFlor4I59G03cxRxV16yUpRrsga6p43333wB2wUAM5DOshQrtADac7bQLiaXHOS64LWDS2QQREDI ggbGDG0HOL5cqJMo0gxYcExWIndUAL3FtRCvGDGJCbCsFhScIJ1lIvGqwpUKSvOm18TEBrFtF8Tx SlRvFdFuG45R1IV8ISOllrGbwhJE2nhh0ZrSwxzv5gAw6rt4tv3AtDeucAJiuGoylQSjcVWb59QA qwTxBp7MIUkdGkuNCAVmyoJ0iByYlQq1b1pegGQqx4MMb4CBhUDKwvvgJZmz00pAALU6IIuU5hOD wCrKUAAwgqy52IjIFSDCG+aQoChIGJhqRrlveouMW4AOX7vcR6XbuDUdJ49woVBxGo1CUWwBDdQG P6Pc0Ch0P0XhsqMaiLBSB8esZ9RhUEoMPlkZKbQ2ohy5cZ37T5J+qwoKi+kOD7u3GNOFD4cKUodq 3it+YcMjVqdFIuxdriHm03ziORTRcmnezAPG92YofDPUTTUcwmtmbZ1s2Xfr74bOMIy4mVwldFwx AOnLwjbL178iETPFv45oyoDKmHWIS1B3Ip3qaFk0l2rv46hjbY5u+YoTQdgONlicOYUJ129YThmO HTWUlEQyTQEjlTJHdfFFBf0J3XUYFYxYvWt27xmWUpokT4KHIoJicDXA/xdyRThQkLFIYjY= --------------Boundary-00=_6EBUCA9ETT9KDWGHCWC8--