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Message-ID: <c1e79c86-56ae-98c6-8dc0-c227f91ee9bc@solarflare.com>
Date: Thu, 6 Sep 2018 15:24:31 +0100
From: Edward Cree <ecree@...arflare.com>
To: <davem@...emloft.net>
CC: <linux-net-drivers@...arflare.com>, <netdev@...r.kernel.org>
Subject: [PATCH v2 net-next 0/4] net: batched receive in GRO path
This series listifies part of GRO processing, in a manner which allows those
packets which are not GROed (i.e. for which dev_gro_receive returns
GRO_NORMAL) to be passed on to the listified regular receive path.
I have not listified dev_gro_receive() itself, or the per-protocol GRO
callback, since GRO's need to hold packets on lists under napi->gro_hash
makes keeping the packets on other lists awkward, and since the GRO control
block state of held skbs can refer only to one 'new' skb at a time.
Nonetheless the batching of the calling code yields some performance gains
in the GRO case as well.
Herewith the performance figures obtained in a NetPerf TCP stream test (with
four streams, and irqs bound to a single core):
net-next: 7.166 Gbit/s (sigma 0.435)
after #2: 7.715 Gbit/s (sigma 0.145) = datum + 7.7%
after #4: 7.890 Gbit/s (sigma 0.217) = datum + 10.1%
(Note that the 'net-next' results were distinctly bimodal, with two results
of about 8 Gbit/s and the remaining ten around 7 Gbit/s. I don't have a
good explanation for this.)
And with GRO disabled through ethtool -K (thus simulating traffic which is
not GRO-able but, being TCP, is still passed to the GRO entry point):
net-next: 4.756 Gbit/s (sigma 0.240)
after #4: 5.355 Gbit/s (sigma 0.232) = datum + 12.6%
v2: Rebased on latest net-next. Removed RFC tags. Otherwise unchanged
owing to lack of comments on v1.
Edward Cree (4):
net: introduce list entry point for GRO
sfc: use batched receive for GRO
net: make listified RX functions return number of good packets
net/core: handle GRO_NORMAL skbs as a list in napi_gro_receive_list
drivers/net/ethernet/sfc/efx.c | 11 +++-
drivers/net/ethernet/sfc/net_driver.h | 1 +
drivers/net/ethernet/sfc/rx.c | 16 +++++-
include/linux/netdevice.h | 6 +-
include/net/ip.h | 4 +-
include/net/ipv6.h | 4 +-
net/core/dev.c | 104 ++++++++++++++++++++++++++--------
net/ipv4/ip_input.c | 39 ++++++++-----
net/ipv6/ip6_input.c | 37 +++++++-----
9 files changed, 157 insertions(+), 65 deletions(-)
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