From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Vlad Yasevich <vyasevic@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Jason Wang <jasowang@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
netdev@vger.kernel.org, KVM list <kvm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: macvtap performance regression (bisected) between 3.13 and 3.14-rc1
Date: Thu, 27 Feb 2014 21:52:22 +0100 [thread overview]
Message-ID: <530FA586.3010400@de.ibm.com> (raw)
Vlad,
commit 6acf54f1cf0a6747bac9fea26f34cfc5a9029523
macvtap: Add support of packet capture on macvtap device.
causes a performance regression for iperf traffic between two KVM guests
on my s390 system. Both guests are connected via two macvtaps on the same OSA
network card.
Before that patch I get ~20 Gbit/sec between two guests, afterwards I get
~4Gbit/sec
Latency seems to be unchanges (uperf 1byte ping pong).
According to ifconfig in the guest, I have ~ 1500 bytes per packet with this
patch and ~ 40000 bytes without. So for some reason this patch causes the
network stack to do segmentation. (the guest kernel stays the same, only host
kernel is changed).
Any ideas?
Christian
next reply other threads:[~2014-02-27 20:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-27 20:52 Christian Borntraeger [this message]
2014-02-28 22:14 ` macvtap performance regression (bisected) between 3.13 and 3.14-rc1 Vlad Yasevich
2014-03-01 11:15 ` Christian Borntraeger
2014-03-01 19:27 ` Vlad Yasevich
2014-03-02 1:21 ` Vlad Yasevich
2014-03-03 9:13 ` Christian Borntraeger
2014-03-03 19:36 ` Vlad Yasevich
2014-03-03 9:11 ` Christian Borntraeger
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