From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751146Ab1ADWut (ORCPT ); Tue, 4 Jan 2011 17:50:49 -0500 Received: from isrv.corpit.ru ([86.62.121.231]:52567 "EHLO isrv.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750871Ab1ADWus (ORCPT ); Tue, 4 Jan 2011 17:50:48 -0500 Message-ID: <4D23A445.5050405@msgid.tls.msk.ru> Date: Wed, 05 Jan 2011 01:50:45 +0300 From: Michael Tokarev Organization: Telecom Service, JSC User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.1.16) Gecko/20101227 Icedove/3.0.11 MIME-Version: 1.0 To: Pavel Machek CC: Linux-kernel , dri-devel@lists.freedesktop.org Subject: Re: VERY slow scrolling on radeon graphics card: debugging a timing issue? References: <4D0FC36D.9010304@msgid.tls.msk.ru> <20110102090001.GB32469@atrey.karlin.mff.cuni.cz> In-Reply-To: <20110102090001.GB32469@atrey.karlin.mff.cuni.cz> X-Enigmail-Version: 1.0.1 OpenPGP: id=804465C5 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 02.01.2011 12:00, Pavel Machek wrote: > Hi! > >> The thing is: that same scrolling becomes much faster >> when I "do something" else while it scrolls up. First >> I noticed this when I wanted to switch to another vt >> while it were scrolling -- I held down Ctrl key on my >> keyboard, and out of the sudden the scroll speed up >> dramatically. >> >> It turned out I can speed the thing to about 10 times >> by generating some load: hit and hold a key on the >> keyboard (generates interrupts?), run kernel compile >> in the background (generates disk interrupts?), move >> mouse... > > Try "irqpoll"? It turned out to be a bit less easy than I thought. The thing is, it appears the issue is not triggered on fresh boot - scrolling is reasonable fast there. But slowness returns back after suspend-to-RAM cycle (not suspend-to-disk). I'm still trying ;) > Will cpu load speed it up, too? (Like yes > /dev/null)? Yes, CPU load fixes the issue immediately. But switching from ondemand to performance CPU governor does not fix it. >> Any hints on where to go from there are apprecated. >> >> The hardware is an AMD780g-based motherboard with >> and Athlon CPU, I've seen the same behavour from >> many other similar boards. Kernels - all up to >> the current 2.6.36.2, sine the old days when kms >> for radeon first appeared in staging. > > Watch /proc/interrupts to see if radeon uses them and if they appear > to work? I don't see any change in radeon interrupt numbers during the scrolling, so it's difficult to say. The IRQ is shared between several devices: $ grep radeon /proc/interrupts 18: 510439 370 IO-APIC-fasteoi ohci_hcd:usb3, ohci_hcd:usb4, ohci_hcd:usb5, radeon The counter changes but very slowly (and not during the scroll test when I don't touch anything), I see on correlation between it any my actions. Thanks! /mjt