linux-kernel - Re: [PATCH v5 2/5] block: loop: set QUEUE_FLAG

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: <CACVXFVOxzqNrUZa9amVVZufH_WaYgBd=Vz0v5dnHbxCjd3gZcQ@mail.gmail.com>
Date:	Mon, 22 Jun 2015 14:32:49 +0800
From:	Ming Lei <ming.lei@...onical.com>
To:	Christoph Hellwig <hch@...radead.org>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Dave Kleikamp <dave.kleikamp@...cle.com>,
	Jens Axboe <axboe@...nel.dk>, Zach Brown <zab@...bo.net>,
	Maxim Patlasov <mpatlasov@...allels.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Tejun Heo <tj@...nel.org>, Dave Chinner <david@...morbit.com>
Subject: Re: [PATCH v5 2/5] block: loop: set QUEUE_FLAG_NOMERGES for request
 queue of loop

On Wed, Jun 10, 2015 at 3:36 PM, Christoph Hellwig <hch@...radead.org> wrote:
> On Tue, Jun 09, 2015 at 09:49:23PM +0800, Ming Lei wrote:
>> It doesn't make sense to enable merge because the I/O
>> submitted to backing file is handled page by page.
>
> Looks fine, but does it make any difference?

Looks no, see the following result, please:

- iops tested by fio: loop over image on HDD.
                         patched  vs. non-patched
    randread     158        161
    read             8716        8784
    randwrite     6076        5893
    write             21896        22066

Thanks,
Ming
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
Please read the FAQ at  http://www.tux.org/lkml/