From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Subject: Re: 2.6.11, IDE: Strange scheduling behaviour: high-pri RT process not scheduled? Date: Wed, 30 Mar 2005 14:06:37 +0200 Message-ID: <58cb370e05033004065b14da51@mail.gmail.com> References: Reply-To: Bartlomiej Zolnierkiewicz Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from wproxy.gmail.com ([64.233.184.200]:2527 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S261854AbVC3MGk (ORCPT ); Wed, 30 Mar 2005 07:06:40 -0500 Received: by wproxy.gmail.com with SMTP id 68so129954wra for ; Wed, 30 Mar 2005 04:06:40 -0800 (PST) In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: kus Kusche Klaus Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org On Wed, 30 Mar 2005 13:52:05 +0200, kus Kusche Klaus wrote: > However, things break seriously when exercising the CF card in parallel > (e.g. with a dd if=/dev/hda of=/dev/null): > > * The rtc *interrupt handler* is delayed for up to 250 *micro*seconds. > This is very bad for my purpose, but easy to explain: It is roughly the > time needed to transfer 512 Bytes from a CF card which can transfer 2 > Mbyte/sec, and obviously, the CPU blocks all interrupts while making pio > > transfers. (Why? Is this really necessary?) > > (I know because I instrumented the rtc irq handler with rdtscl(), too) hdparm -u1 /dev/hda should help