From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joachim Foerster Subject: AHCI performance and IRQ load Date: Fri, 23 Nov 2012 17:02:23 +0100 Message-ID: <50AF9E0F.8030300@missinglinkelectronics.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from static.204.45.9.5.clients.your-server.de ([5.9.45.204]:48975 "EHLO smtp.missinglinkelectronics.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755145Ab2KWQIa (ORCPT ); Fri, 23 Nov 2012 11:08:30 -0500 Received: from localhost (code.missinglinkelectronics.com [127.0.0.1]) by smtp.missinglinkelectronics.com (Postfix) with ESMTP id 6847B79203D for ; Fri, 23 Nov 2012 17:02:29 +0100 (CET) Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-ide@vger.kernel.org Cc: Lorenz Kolb Hi all, we are currently working on a high performance storage test solution=20 using SATA/AHCI. Due to having performance issues with small block size= s=20 (high interrupt load), we did some research and came across a FAST12=20 paper by Intel: "When Poll is Better than Interrupt". The authors do suggest a synchronous completion model or even a hybrid=20 mode with support for async and sync completion - for future SSDs. Does anybody know, if there already is work going on to incorporate suc= h=20 functionality into the block layer & backends (meaning, among others:=20 libata/ahci)? Another thing, which seemed promising was AHCI's=20 CommandCompletionCoalescing (CCC) feature. However most AHCI controller= s=20 don't seem to support this feature. Anybody aware of AHCI controllers having CCC support? There seemed to be a discussion about CCC support for the ahci driver=20 some years ago http://www.spinics.net/lists/linux-ide/msg02994.html, bu= t=20 obviously no code came out of it - or is there a known patchset? Thanks, --=20 Joachim F=F6rster Direct DE: +49 (731) 141-149-42 Missing Link Electronics http://www.missinglinkelectronics.com Office DE: +49 (731) 141-149-0 Office US: +1 (408) 457-0700