From: Benjamin LaHaise <ben.lahaise@neterion.com>
To: netdev@vger.kernel.org
Subject: [4/6] vxge: prefetch RxD descriptors
Date: Tue, 4 Aug 2009 16:21:39 -0400 [thread overview]
Message-ID: <20090804202139.GE9924@neterion.com> (raw)
This patch prefetches RxD descriptors which helps to lower the latency of a
cache miss in vxge_hw_ring_rxd_next_completed. This lowers the % of CPU
time used by vxge_hw_ring_rxd_next_completed() where the descriptor is
accessed in profiling netperf on a P4 Xeon from 1.5% to 1.0%.
Signed-off-by: Benjamin LaHaise <ben.lahaise@neterion.com>
Signed-off-by: Sreenivasa Honnur <sreenivasa.honnur@neterion.com>
Signed-off-by: Ramkrishna Vepa <ram.vepa@neterion.com>
---
--- a/drivers/net/vxge/vxge-main.c.orig 2009-05-04 15:04:14.000000000 -0700
+++ b/drivers/net/vxge/vxge-main.c 2009-05-04 14:58:48.000000000 -0700
@@ -445,6 +431,7 @@ vxge_rx_1b_compl(struct __vxge_hw_ring *
vxge_hw_ring_replenish(ringh, 0);
do {
+ prefetch((char *)dtr + L1_CACHE_BYTES);
rx_priv = vxge_hw_ring_rxd_private_get(dtr);
skb = rx_priv->skb;
data_size = rx_priv->data_size;
diff --git a/drivers/net/vxge/vxge-traffic.c b/drivers/net/vxge/vxge-traffic.c
index 7be0ae1..9a6b10d 100644
--- a/drivers/net/vxge/vxge-traffic.c
+++ b/drivers/net/vxge/vxge-traffic.c
@@ -731,6 +731,7 @@ vxge_hw_channel_dtr_try_complete(struct __vxge_hw_channel *channel, void **dtrh)
vxge_assert(channel->compl_index < channel->length);
*dtrh = channel->work_arr[channel->compl_index];
+ prefetch(*dtrh);
}
/*
reply other threads:[~2009-08-04 20:39 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20090804202139.GE9924@neterion.com \
--to=ben.lahaise@neterion.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).