From: Kevin Wolf <kwolf@redhat.com>
To: Orit Wasserman <owasserm@redhat.com>
Cc: pbonzini@redhat.com, quintela@redhat.com, chegu_vinod@hp.com,
qemu-devel@nongnu.org, mst@redhat.com
Subject: Re: [Qemu-devel] [PATCH v5 7/7] Use qemu_put_buffer_async for guest memory pages
Date: Fri, 5 Apr 2013 15:44:45 +0200 [thread overview]
Message-ID: <20130405134445.GD2351@dhcp-200-207.str.redhat.com> (raw)
In-Reply-To: <1363963683-26157-8-git-send-email-owasserm@redhat.com>
Am 22.03.2013 um 15:48 hat Orit Wasserman geschrieben:
> This will remove an unneeded copy of guest memory pages.
> For the page header and device state we still copy the data to the
> static buffer the other option is to allocate the memory on demand
> which is more expensive.
>
> Signed-off-by: Orit Wasserman <owasserm@redhat.com>
This seems to have killed savevm performance. I noticed that
qemu-iotests case 007 took forever on my test box (882 seconds instead
of something like 10 seconds). It can be reproduced by this script:
export MALLOC_PERTURB_=11
qemu-img create -f qcow2 -o compat=1.1 test.qcow2 1M
time qemu-system-x86_64 -nographic -hda $TEST_IMG -serial none -monitor stdio <<EOF
savevm test
quit
EOF
This used to take about 0.6s for me, after this patch it's around 10s.
Kevin
next prev parent reply other threads:[~2013-04-05 13:44 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-22 14:47 [Qemu-devel] [PATCH v5 0/7] Migration: Remove copying of guest ram pages Orit Wasserman
2013-03-22 14:47 ` [Qemu-devel] [PATCH v5 1/7] Add QemuFileWritevBuffer QemuFileOps Orit Wasserman
2013-03-22 14:47 ` [Qemu-devel] [PATCH v5 2/7] Add socket_writev_buffer function Orit Wasserman
2013-03-22 14:47 ` [Qemu-devel] [PATCH v5 3/7] Update bytes_xfer in qemu_put_byte Orit Wasserman
2013-03-22 14:48 ` [Qemu-devel] [PATCH v5 4/7] Store the data to send also in iovec Orit Wasserman
2013-03-22 14:48 ` [Qemu-devel] [PATCH v5 5/7] Use writev ops if available Orit Wasserman
2013-03-22 14:48 ` [Qemu-devel] [PATCH v5 6/7] Add qemu_put_buffer_async Orit Wasserman
2013-03-22 14:48 ` [Qemu-devel] [PATCH v5 7/7] Use qemu_put_buffer_async for guest memory pages Orit Wasserman
2013-04-05 13:44 ` Kevin Wolf [this message]
2013-04-05 15:23 ` Paolo Bonzini
2013-04-05 15:39 ` Kevin Wolf
2013-04-05 15:42 ` Paolo Bonzini
2013-04-05 15:56 ` Kevin Wolf
2013-03-27 21:27 ` [Qemu-devel] [PATCH v5 0/7] Migration: Remove copying of guest ram pages Eric Blake
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