From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 8BB546B0173 for ; Sun, 31 Oct 2010 13:49:41 -0400 (EDT) Received: by gyh20 with SMTP id 20so3148563gyh.14 for ; Sun, 31 Oct 2010 10:49:40 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20101031023145.GB1869@thunk.org> References: <20101028090002.GA12446@elte.hu> <20101028133036.GA30565@elte.hu> <20101028170132.GY27796@think> <20101029145212.GA21205@thunk.org> <20101030091440.GA15276@elte.hu> <20101031023145.GB1869@thunk.org> Date: Sun, 31 Oct 2010 18:49:39 +0100 Message-ID: Subject: Re: 2.6.36 io bring the system to its knees From: Corrado Zoccolo Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Ted Ts'o , Aidar Kultayev , Ingo Molnar , Pekka Enberg , Chris Mason , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Andrew Morton , Jens Axboe , Peter Zijlstra , Nick Piggin , Arjan van de Ven , Thomas Gleixner List-ID: On Sun, Oct 31, 2010 at 3:31 AM, Ted Ts'o wrote: > On Sat, Oct 30, 2010 at 07:02:35PM +0600, Aidar Kultayev wrote: >> the system is/was doing : >> .dd if=3D/dev/zero of=3Dtest.10g bs=3D1M count=3D10000;rm test.10g >> .netbeans >> .compiling gcc-4.5.1 >> .running VBox, which wasn't doing any IO. The guest os was idle in other= words >> .vlc >> .chromium >> .firefox >> and bunch of other small stuff. >> >> Even without having running DD, the mouse cursor would occasionally >> lag. The alt+tab effect in KWin would take 5+seconds to workout. >> When I run DD on top of the workload it consistently made system much >> more laggy. The cursor would freeze much more frequent. It is like if >> you drag your mouse physically, but the cursor on the screen would >> jump discretely, in other words there is no continuity. >> Music would stop. > > If you start shutting down tasks, Vbox, netbeans, chromium, etc., at > what point does the cursor start tracking the system easily? =C2=A0Is the > system swapping? =C2=A0Do you know how to use tools like dstat or iostat = to > see if the system is actively writing to the swap partition? =C2=A0(And a= re > you using a swap partition or a swap file?) > > The fact that cursor isn't tracking well even when the dd is running, > and presumably the only source of I/O is the gcc and vlc, makes me > suspect that you may be swapping pretty heavily. =C2=A0Have you tried > investigating that possibility, and made sure it has been ruled out? Something to try is also to raise X cpu scheduling priority, since I would be really surprised if we evict from memory the routine that draws the cursor. BTW, I've seen the cursor jumping problem even when not swapping, and with minimal *real* disk activity (but with heavy usage of a fuse filesystem providing remote resources), and high cpu activity. Raising X priority solved the problem with the mouse pointer, but the gui programs still didn't respond quickly... Thanks Corrado > > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0- Ted > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. =C2=A0For more info on Linux MM, > see: http://www.linux-mm.org/ . > Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ > Don't email: email@kvack.org > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org