From: Rusty Russell Date: Thu, 12 Jan 2012 05:14:42 +0000 (+1030) Subject: virtio: harsher barriers for rpmsg. X-Git-Tag: v3.3-rc1~85^2~23 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7b21e34fd1c272e3a8c3846168f2f6287a4cd72b;p=pandora-kernel.git virtio: harsher barriers for rpmsg. We were cheating with our barriers; using the smp ones rather than the real device ones. That was fine, until rpmsg came along, which is used to talk to a real device (a non-SMP CPU). Unfortunately, just putting back the real barriers (reverting d57ed95d) causes a performance regression on virtio-pci. In particular, Amos reports netbench's TCP_RR over virtio_net CPU utilization increased up to 35% while throughput went down by up to 14%. By comparison, this branch is in the noise. Reference: https://lkml.org/lkml/2011/12/11/22 Signed-off-by: Rusty Russell --- Reading git-diff-tree failed