diff options
| author | Yuchung Cheng <ycheng@google.com> | 2018-09-27 11:21:19 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-09-29 11:22:22 -0700 |
| commit | a337531b942bd8a03e7052444d7e36972aac2d92 (patch) | |
| tree | 32b97fbbf43d08936e0fbe9227158b0ea6508d36 /net/ipv4/tcp.c | |
| parent | 3ff6cde846857d45193b5be249e3ffd1bed4aea1 (diff) | |
tcp: up initial rmem to 128KB and SYN rwin to around 64KB
Previously TCP initial receive buffer is ~87KB by default and
the initial receive window is ~29KB (20 MSS). This patch changes
the two numbers to 128KB and ~64KB (rounding down to the multiples
of MSS) respectively. The patch also simplifies the calculations s.t.
the two numbers are directly controlled by sysctl tcp_rmem[1]:
1) Initial receiver buffer budget (sk_rcvbuf): while this should
be configured via sysctl tcp_rmem[1], previously tcp_fixup_rcvbuf()
always override and set a larger size when a new connection
establishes.
2) Initial receive window in SYN: previously it is set to 20
packets if MSS <= 1460. The number 20 was based on the initial
congestion window of 10: the receiver needs twice amount to
avoid being limited by the receive window upon out-of-order
delivery in the first window burst. But since this only
applies if the receiving MSS <= 1460, connection using large MTU
(e.g. to utilize receiver zero-copy) may be limited by the
receive window.
With this patch TCP memory configuration is more straight-forward and
more properly sized to modern high-speed networks by default. Several
popular stacks have been announcing 64KB rwin in SYNs as well.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 69c236943f56..dcf51fbf5ec7 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3896,8 +3896,8 @@ void __init tcp_init(void) init_net.ipv4.sysctl_tcp_wmem[2] = max(64*1024, max_wshare); init_net.ipv4.sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; - init_net.ipv4.sysctl_tcp_rmem[1] = 87380; - init_net.ipv4.sysctl_tcp_rmem[2] = max(87380, max_rshare); + init_net.ipv4.sysctl_tcp_rmem[1] = 131072; + init_net.ipv4.sysctl_tcp_rmem[2] = max(131072, max_rshare); pr_info("Hash tables configured (established %u bind %u)\n", tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size); |