linux-kernel - Re: [PATCH V4 07/15] blk-throttle: make throtl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20161122212715.GD17534@htj.duckdns.org>
Date:   Tue, 22 Nov 2016 16:27:15 -0500
From:   Tejun Heo <tj@...nel.org>
To:     Shaohua Li <shli@...com>
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        Kernel-team@...com, axboe@...com, vgoyal@...hat.com
Subject: Re: [PATCH V4 07/15] blk-throttle: make throtl_slice tunable

Hello,

On Mon, Nov 14, 2016 at 02:22:14PM -0800, Shaohua Li wrote:
> throtl_slice is important for blk-throttling. A lot of stuffes depend on
> it, for example, throughput measurement. It has 100ms default value,
> which is not appropriate for all disks. For example, for SSD we might
> use a smaller value to make the throughput smoother. This patch makes it
> tunable.

It bothers me a bit because time slice doesn't mean anything inherent
to throttling.  It really is an implementation detail - throttling can
be implemented at per-operation level without time slice involved at
all.  It's okay to expose the knob if necessary but the meaning of the
knob is almost completely arbitrary to users (as it has no inherent
meaning).

Thanks.

-- 
tejun