From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753591AbbHMS6H (ORCPT ); Thu, 13 Aug 2015 14:58:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36095 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752061AbbHMS6F (ORCPT ); Thu, 13 Aug 2015 14:58:05 -0400 From: Jeff Moyer To: axboe@kernel.dk, hch@infradead.org Cc: ed.cashin@acm.org, linux-kernel@vger.kernel.org Subject: [PATCH 0/2] block: Reinstate BLK_DEF_MAX_SECTORS Date: Thu, 13 Aug 2015 14:57:55 -0400 Message-Id: <1439492277-14638-1-git-send-email-jmoyer@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 34b48db66e08 (block: remove artificial max_hw_sectors cap) caused performance regressions for streaming I/O workloads across a range of storage from SATA disks to enterprise storage arrays. I was unable to actually show a performance gain for any storage I have access to. However, the patch was introduced to boost performance on software RAID over SATA disks, and I don't have access to such a configuration. The compromise is to reinstate BLK_DEF_MAX_SECTORS, but to bump it up to 2560 from 1024. This number should allow full stripe writes to 10 data disks with a chunk size of 128KB, and at the same time does not regress the storage I have access to. [PATCH 1/2] Revert "block: remove artifical max_hw_sectors cap" [PATCH 2/2] block: bump BLK_DEF_MAX_SECTORS to 2560 block/blk-settings.c | 4 +++- drivers/block/aoe/aoeblk.c | 2 +- include/linux/blkdev.h | 1 + 3 files changed, 5 insertions(+), 2 deletions(-)