From mboxrd@z Thu Jan  1 00:00:00 1970
From: Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH 3/4] dm stats: report histogram of latencies
Date: Tue, 16 Jun 2015 12:21:10 -0400
Message-ID: <20150616162110.GA14943@redhat.com>
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Cc: Mike Snitzer <msnitzer@redhat.com>, Laurence Oberman <loberman@redhat.com>, Tao Ma <boyu.mt@taobao.com>, Robin Dong <sanbai@alibaba-inc.com>, Coly Li <colyli@gmail.com>, "Alasdair G. Kergon" <agk@redhat.com>
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On Tue, Jun 09, 2015 at 05:22:05PM -0400, Mikulas Patocka wrote:
> This patch adds an option to dm statistics to collect and report the
> histogram of latencies.
> 
> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

I am wondering how does histogram help. IOW, if disks are bad, will
average latencies not go up as well and that one can already calcualte
using existing stats.

Thanks
Vivek