From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-f68.google.com ([209.85.221.68]:44364 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727462AbeHQUjg (ORCPT ); Fri, 17 Aug 2018 16:39:36 -0400 Received: by mail-wr1-f68.google.com with SMTP id r16-v6so7704817wrt.11 for ; Fri, 17 Aug 2018 10:35:21 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) Subject: Re: blk-mq 5-8 times slower for bmap-tools From: Paolo Valente In-Reply-To: Date: Fri, 17 Aug 2018 19:35:18 +0200 Cc: linux-block@vger.kernel.org, Ben Hutchings Message-Id: <5F152F61-4DBE-4394-939B-D5F82EEE72AE@linaro.org> References: To: Ricardo Ribalda Delgado Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org > Il giorno 17 ago 2018, alle ore 19:31, Ricardo Ribalda Delgado = ha scritto: >=20 > Hello >=20 > Coming from: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=3D906328 >=20 > bmaptools is kind of a "smart dd" tool, that lets you write images > very fast and securely. Since the last Debian Kernel update it has > become 5-8 times slower. >=20 > After some debugging, we have figured out that the reason for that > slowness is the Multi-Queue Block IO Queueing Mechanism. >=20 > Debian maintainer has pointed out that in the near future the single > queue will be deprecated. >=20 > My question is if we can get a similar perfomance for bmaptools with > blk-mq and how? >=20 Have you also checked what happens after switching to a different I/O scheduler for the involved drive (among none, mq-deadline, bfq and kyber)? Paolo > Thanks! >=20 > --=20 > Ricardo Ribalda