From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751728AbWEPR1M (ORCPT ); Tue, 16 May 2006 13:27:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751730AbWEPR1M (ORCPT ); Tue, 16 May 2006 13:27:12 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:12423 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S1751727AbWEPR1L (ORCPT ); Tue, 16 May 2006 13:27:11 -0400 Message-ID: <446A0B6C.8050901@garzik.org> Date: Tue, 16 May 2006 13:27:08 -0400 From: Jeff Garzik User-Agent: Thunderbird 1.5.0.2 (X11/20060501) MIME-Version: 1.0 To: Kevin Radloff CC: Alan Cox , linux-kernel@vger.kernel.org Subject: Re: PATCH: Fix broken PIO with libata References: <1147790393.2151.62.camel@localhost.localdomain> <3b0ffc1f0605160833k5f6355c5n3f2a9ab1b211a95@mail.gmail.com> <1147794791.2151.71.camel@localhost.localdomain> <3b0ffc1f0605161019j7149f72bv309db19eb9d12dd8@mail.gmail.com> In-Reply-To: <3b0ffc1f0605161019j7149f72bv309db19eb9d12dd8@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.1 (----) X-Spam-Report: SpamAssassin version 3.1.1 on srv5.dvmed.net summary: Content analysis details: (-4.1 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Kevin Radloff wrote: > On 5/16/06, Alan Cox wrote: >> On Maw, 2006-05-16 at 11:33 -0400, Kevin Radloff wrote: >> > However, I still have a problem with pata_pcmcia (that I actually >> > experienced also with the ide-cs driver) where sustained reading or >> > writing to the CF card spikes the CPU with nearly 100% system time. >> >> That is normal. The PCMCIA devices don't support DMA. As a result of >> this the processor has to fetch each byte itself over the ISA speed >> PCMCIA bus link. > > Hrm, as I recall that only started happening with ide-cs sometime in > the single digits of 2.6.x.. And note that it's only maxing out at > about 1.5MB/s. Should that saturate my laptop's 1.1GHz Pentium M > processor? Doing data xfer using PIO rather than DMA definitely eats tons of CPU cycles. Jeff