From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762025AbYDOUVg (ORCPT ); Tue, 15 Apr 2008 16:21:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752748AbYDOUV2 (ORCPT ); Tue, 15 Apr 2008 16:21:28 -0400 Received: from smtpq1.tilbu1.nb.home.nl ([213.51.146.200]:43340 "EHLO smtpq1.tilbu1.nb.home.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751618AbYDOUV2 (ORCPT ); Tue, 15 Apr 2008 16:21:28 -0400 Message-ID: <48050EF1.8050507@keyaccess.nl> Date: Tue, 15 Apr 2008 22:24:17 +0200 From: Rene Herman User-Agent: Thunderbird 2.0.0.12 (X11/20080213) MIME-Version: 1.0 To: "Lev A. Melnikovsky" CC: Alessandro Suardi , David Brownell , Linux Kernel Subject: Re: ehci-hcd affects hda speed References: <200803171700.26274.david-b@pacbell.net> <47DF19AD.405@keyaccess.nl> <200803171855.44552.david-b@pacbell.net> <47E1B062.4060709@keyaccess.nl> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: 0.0 (/) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15-04-08 21:56, Lev A. Melnikovsky wrote: > Sorry, I had virtually no time to answer earlier. If (hopefully) someone > is still interested, here's my feedback Interested yes, although being no longer in posession of the hardware it's a somewhat academic interest... > I have repeated experiments with P3B-F and VT6212L combination (to > improve visibility the AsyncSchedSleepTime is set to 1us): > > #0. Nothing is connected to USB, no ehci-hcd loaded > hda throughput 28+-1MB/s > > #1. ehci-hcd loaded, still no USB peripherals > hda throughput 28+-1 MB/s > > #2. Something (USB hub and FLASH drive tested) is attached > hda throughput 15+-1 MB/s > > #3. All USB peripherals are removed > hda throughput 15+-1 MB/s > > #4. ehci-hcd is rmmod'ed > hda throughput 28+-1MB/s > > The oddest peculiarity for me is the hysteretic difference between #1 and > #3 states. I mean experimental data (hda throughput) depends not on the > state (hardware/loaded modules), but on the path we followed. On the chip having inited itself at least. Yes, your results match what I experienced. > Interestingly enough, sampling registers (via /sys) often shows Async bit > set of the status register in the state #3. It is always cleared in #1. > The async file is empty in both states. I wonder, how many degrees of > freedom does an empty schedule have? Does "empty" mean "has no incomplete > requests" or "has no requests at all"? Just guessing... Should leave this up to David, but as far as I'm aware "no at all". > RH> The sleep time wasn't the core problem, so I wonder of later VIA chips do > RH> still have the active async schedule problem... > I don't think this is purely VIA problem. I did not _try_ to install that > VT6212L card into newer motherboard, but my _feeling_ is that we see an > "incompatibility" between older PCI mobo chipsets and VIA USB controller. I very much doubt that. Can't really imagine an off-silicon reason the chip would keep scanning the async schedule. I'm also now using a NEC controller card in that same machine and it also shows no problems. > Actually, taking into account superior PCI bandwidth of modern PCs (if > compared with my old P3B-F motherboard) I am not sure we can perform a > clean reliable test without PCI bus analyzer. http://lkml.org/lkml/2005/5/30/259 > > -l >