diff options
author | Eric Dumazet | 2014-09-24 04:11:22 -0700 |
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committer | David S. Miller | 2014-09-28 16:36:48 -0400 |
commit | cd7d8498c9a5d510c64db38d9f4f4fbc41790f09 (patch) | |
tree | 4057e715ca8227a081db71f1ec1359011c5c1a00 /README | |
parent | dc83d4d8f6c897022c974a00769b7a6efee6aed8 (diff) |
tcp: change tcp_skb_pcount() location
Our goal is to access no more than one cache line access per skb in
a write or receive queue when doing the various walks.
After recent TCP_SKB_CB() reorganizations, it is almost done.
Last part is tcp_skb_pcount() which currently uses
skb_shinfo(skb)->gso_segs, which is a terrible choice, because it needs
3 cache lines in current kernel (skb->head, skb->end, and
shinfo->gso_segs are all in 3 different cache lines, far from skb->cb)
This very simple patch reuses space currently taken by tcp_tw_isn
only in input path, as tcp_skb_pcount is only needed for skb stored in
write queue.
This considerably speeds up tcp_ack(), granted we avoid shinfo->tx_flags
to get SKBTX_ACK_TSTAMP, which seems possible.
This also speeds up all sack processing in general.
This speeds up tcp_sendmsg() because it no longer has to access/dirty
shinfo.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'README')
0 files changed, 0 insertions, 0 deletions