From mboxrd@z Thu Jan 1 00:00:00 1970
From: bugzilla-daemon@bugzilla.kernel.org
Subject: [Bug 71641] Unreasonable performance degradation in ext4 with full
data journaling
Date: Wed, 26 Mar 2014 13:40:42 +0000
Message-ID:
References:
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
To: linux-ext4@vger.kernel.org
Return-path:
Received: from mail.kernel.org ([198.145.19.201]:50489 "EHLO mail.kernel.org"
rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
id S1753526AbaCZNkp (ORCPT );
Wed, 26 Mar 2014 09:40:45 -0400
Received: from mail.kernel.org (localhost [127.0.0.1])
by mail.kernel.org (Postfix) with ESMTP id 7F62120221
for ; Wed, 26 Mar 2014 13:40:44 +0000 (UTC)
Received: from bugzilla2.web.kernel.org (bugzilla2.web.kernel.org [172.20.200.52])
by mail.kernel.org (Postfix) with ESMTP id 4718E201BC
for ; Wed, 26 Mar 2014 13:40:43 +0000 (UTC)
In-Reply-To:
Sender: linux-ext4-owner@vger.kernel.org
List-ID:
https://bugzilla.kernel.org/show_bug.cgi?id=71641
--- Comment #8 from Theodore Tso ---
it's clear this isn't going to get performance up to 1.1 GB/s, but I'm curious
how much setting JBD2_NR_BATCH changes things at 512 and 1024 and possibly even
2048. Once it no longer maters a difference, if you could do another
blktrace, and also gather lock_stat information, that would be useful.
To gather lock_stat information, enable CONFIG_LOCK_STAT, and then "echo 0 >
/proc/lock_stat" before you start the workload, and then capture the output of
/proc/lock_stat after you finish running your workload/benchmark.
If you also regather numbers with lock_stat enabled on a stock 3.11 kernel (and
also get a /proc/lock_stat report from a stock 3.11 kernel, with and without
data=journal), that would be useful.
If it turns out that there is some lock contention going on with some of the
jbd2 spinlocks, there are some patches queued for 3.15 that I may have to ask
you to try (which will mean going to something like 3.14-rc7 plus some
additional patches from the ext4 git tree).
Thanks for your benchmarking!
--
You are receiving this mail because:
You are watching the assignee of the bug.