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From: Anthony Liguori <anthony@codemonkey.ws>
To: Saul Tamari <stamari@gmail.com>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: [Qemu-devel] Re: [PATCH] qemu-kvm: clear only essential parts of VirtIOBlockReq on object allocation - RESUBMIT
Date: Tue, 17 Nov 2009 13:39:16 -0600	[thread overview]
Message-ID: <4B02FBE4.2060409@codemonkey.ws> (raw)
In-Reply-To: <41be791c0911091004x62d30fbey91ef730475ba3571@mail.gmail.com>

Saul Tamari wrote:
> This patch reduces the size of memory being cleared on every virtio-blk IO.
>
> Improve number of IOPS when using avirtio-blk device.
>
> On every virtio-blk IO command passed to QEMU, virtio_blk_alloc_request()
> allocates and clears (with qemu_mallocz()) a VirtIOBlockReq object.
> The sizeof(VirtIOBlockReq) equals 41040 bytes on my x86-64 machine.
> By moving the 'elem' variable to the end of VirtIOBlockReq and
> clearing only upto the address of the 'elem.in_addr' field, the
> memset() call now clears only 80 bytes.
>
>
> Signed-off-by: Saul Tamari <stamari@gmail.com>
> ---
>
> diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
> index 2630b99..de74b00 100644
> --- a/hw/virtio-blk.c
> +++ b/hw/virtio-blk.c
> @@ -79,12 +79,13 @@ static inline void virtio_identify_template(struct
> virtio_blk_config *bc)
>   

This patch is whitespace damaged by your mailer.

Regards,

Anthony Liguori

  reply	other threads:[~2009-11-17 19:39 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-09 18:04 [Qemu-devel] [PATCH] qemu-kvm: clear only essential parts of VirtIOBlockReq on object allocation - RESUBMIT Saul Tamari
2009-11-17 19:39 ` Anthony Liguori [this message]
2009-11-18 14:41   ` [Qemu-devel] " Saul Tamari

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