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David Vrabel authored
Always fully coalesce guest Rx packets into the minimum number of ring slots. Reducing the number of slots per packet has significant performance benefits when receiving off-host traffic. Results from XenServer's performance benchmarks: Baseline Full coalesce Interhost VM receive 7.2 Gb/s 11 Gb/s Interhost aggregate 24 Gb/s 24 Gb/s Intrahost single stream 14 Gb/s 14 Gb/s Intrahost aggregate 34 Gb/s 34 Gb/s However, this can increase the number of grant ops per packet which decreases performance of backend (dom0) to VM traffic (by ~10%) /unless/ grant copy has been optimized for adjacent ops with the same source or destination (see "grant-table: defer releasing pages acquired in a grant copy"[1] expected in Xen 4.6). [1] http://lists.xen.org/archives/html/xen-devel/2015-01/msg01118.htmlSigned-off-by:
David Vrabel <david.vrabel@citrix.com> Acked-by:
Ian Campbell <ian.campbell@citrix.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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