Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 19 Dec 2001 04:17:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 19 Dec 2001 04:17:03 -0500 Received: from mail.loewe-komp.de ([62.156.155.230]:28167 "EHLO mail.loewe-komp.de") by vger.kernel.org with ESMTP id ; Wed, 19 Dec 2001 04:16:57 -0500 Message-ID: <3C205B9A.8F8BFEC7@loewe-komp.de> Date: Wed, 19 Dec 2001 10:19:22 +0100 From: Peter =?iso-8859-1?Q?W=E4chtler?= Organization: LOEWE. Hannover X-Mailer: Mozilla 4.78 [de] (X11; U; Linux 2.4.16 i686) X-Accept-Language: de, en MIME-Version: 1.0 To: Doug Ledford CC: Kernel Mailing List Subject: Re: Scheduler ( was: Just a second ) ... In-Reply-To:

<20011218105459.X855@lynx.no> <3C1F8A9E.3050409@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Doug Ledford schrieb: > > Andreas Dilger wrote: > > > On Dec 18, 2001 09:27 -0800, Linus Torvalds wrote: > > > >>Maybe the best thing to do is to educate the people who write the sound > >>apps for Linux (somebody was complaining about "esd" triggering this, for > >>example). > >> > > > > Yes, esd is an interrupt hog, it seems. When reading this thread, I > > checked, and sure enough I was getting 190 interrupts/sec on the > > sound card while not playing any sound. I killed esd (which I don't > > use anyways), and interrupts went to 0/sec when not playing sound. > > Still at 190/sec when using mpg123 on my ymfpci (Yamaha YMF744B DS-1S) > > sound card. > > Weel, evidently esd and artsd both do this (well, I assume esd does now, it > didn't do this in the past). Basically, they both transmit silence over the > sound chip when nothing else is going on. So even though you don't hear > anything, the same sound output DMA is taking place. That avoids things > like nasty pops when you start up the sound hardware for a beep and that > sort of thing. It also maintains state where as dropping output entirely > could result in things like module auto unloading and then reloading on the > next beep, etc. Personally, the interrupt count and overhead annoyed me > enough that when I started hacking on the i810 sound driver one of my > primary goals was to get overhead and interrupt count down. I think I > suceeded quite well. On my current workstation: > > Context switches per second not playing any sound: 8300 - 8800 > Context switches per second playing an MP3: 9200 - 9900 > Interrupts per second from sound device: 86 > %CPU used when not playing MP3: 0 - 3% (magicdev is a CPU pig once every 2 > seconds) > %CPU used when playing MP3s: 0 - 4% > > In any case, it might be worth the original poster's time in figuring out > just how much of his lost CPU is because of playing sound and how much is > actually caused by the windowing system and all the associated bloat that > comes with it now a days. > Do you really think 8000 context switches are sane? pippin:/var/log # vmstat 1 procs memory swap io system cpu r b w swpd free buff cache si so bi bo in cs us sy id 2 0 0 100728 4424 121572 27800 0 1 6 6 61 77 98 2 0 2 0 0 100728 5448 121572 27800 0 0 0 68 112 811 93 7 0 2 0 0 100728 5448 121572 27800 0 0 0 0 101 776 95 5 0 3 0 0 100728 4928 121572 27800 0 0 0 0 101 794 92 8 0 having a load ~2.1 (2 seti@home) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/