Commit 761965ea authored Dec 04, 2011 by Eric Dumazet Committed by David S. Miller Dec 04, 2011

tcp: tcp_sendmsg() page recycling



If our TCP_PAGE(sk) is not shared (page_count() == 1), we can set page
offset to 0.

This permits better filling of the pages on small to medium tcp writes.

"tbench 16" results on my dev server (2x4x2 machine) :

Before : 3072 MB/s
After  : 3146 MB/s  (2.4 % gain)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 117632e6

net/ipv4/tcp.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -1009,7 +1009,12 @@ new_segment:
		int merge = 0;
		int i = skb_shinfo(skb)->nr_frags;
		struct page *page = TCP_PAGE(sk);
		int off = TCP_OFF(sk);
		int off;

		if (page && page_count(page) == 1)
		TCP_OFF(sk) = 0;

		off = TCP_OFF(sk);

		if (skb_can_coalesce(skb, i, page, off) &&
		off != PAGE_SIZE) {