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From: Seth Forshee <seth.forshee@canonical.com>
To: "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org
Subject: Performance regression with virtio_net
Date: Thu, 27 Jul 2017 12:09:42 -0500	[thread overview]
Message-ID: <20170727170942.ub24lwgrl3x2outp@ubuntu-hedt> (raw)

I'm seeing a performance regression with virtio_net that looks to have
started in 4.12-rc1. I only see it in one context though, downloading
snap packages from the Ubuntu snap store. For example:

 https://api.snapcraft.io/api/v1/snaps/download/b8X2psL1ryVrPt5WEmpYiqfr5emixTd7_1797.snap

which redirects to Internap's CDN. Normally this downloads in a few
seconds at ~10 MB/s, but with 4.12 and 4.13 it takes minutes with a rate
of ~150 KB/s. Everything else I've tried downloads as normal speeds.

I bisected this to 680557cf79f8 "virtio_net: rework mergeable buffer
handling". If I revert this on top of 4.13-rc2 (along with other changes
needed to successfully revert it) speeds return to normal.

Thanks,
Seth

             reply	other threads:[~2017-07-27 17:09 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-27 17:09 Seth Forshee [this message]
2017-07-27 20:38 ` Performance regression with virtio_net Michael S. Tsirkin
2017-07-27 21:14   ` Seth Forshee
2017-07-27 21:30     ` Michael S. Tsirkin
2017-07-28 13:12       ` Seth Forshee
  -- strict thread matches above, loose matches on Subject: below --
2017-07-30 22:25 Euan Kemp
2017-07-31 13:26 ` Michael S. Tsirkin
2017-07-31 14:29   ` Seth Forshee
2017-07-31 18:38   ` Euan Kemp
2017-07-31 18:50     ` Michael S. Tsirkin

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