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| author | Eric Dumazet <[email protected]> | 2013-05-15 19:25:55 +0000 |
|---|---|---|
| committer | David S. Miller <[email protected]> | 2013-05-16 22:19:45 +0000 |
| commit | d2cf43674e17ca1c16c68d46d987d2f17bf7c371 (patch) | |
| tree | f308a56b13f27297349f44f785f3c5d0d651ac07 /drivers/net/xen-netback/interface.c | |
| parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net (diff) | |
| download | kernel-d2cf43674e17ca1c16c68d46d987d2f17bf7c371.tar.gz kernel-d2cf43674e17ca1c16c68d46d987d2f17bf7c371.zip | |
tcp: speedup tcp_fixup_rcvbuf()
tcp_fixup_rcvbuf() contains a loop to estimate initial socket
rcv space needed for a given mss. With large MTU (like 64K on lo),
we can loop ~500 times and consume a lot of cpu cycles.
perf top of 200 concurrent netperf -t TCP_CRR
5.62% netperf [kernel.kallsyms] [k] tcp_init_buffer_space
1.71% netperf [kernel.kallsyms] [k] _raw_spin_lock
1.55% netperf [kernel.kallsyms] [k] kmem_cache_free
1.51% netperf [kernel.kallsyms] [k] tcp_transmit_skb
1.50% netperf [kernel.kallsyms] [k] tcp_ack
Lets use a 100% factor, and remove the loop.
100% is needed anyway for tcp_adv_win_scale=1
default value, and is also the maximum factor.
Refs: commit b49960a05e32
("tcp: change tcp_adv_win_scale and tcp_rmem[2]")
Signed-off-by: Eric Dumazet <[email protected]>
Cc: Neal Cardwell <[email protected]>
Cc: Yuchung Cheng <[email protected]>
Acked-by: Neal Cardwell <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Diffstat (limited to 'drivers/net/xen-netback/interface.c')
0 files changed, 0 insertions, 0 deletions