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| author | Dust Li <dust.li@linux.alibaba.com> | 2022-03-01 12:44:00 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-03-01 17:25:12 +0300 |
| commit | 6bf536eb5c8ca011d1ff57b5c5f7c57ceac06a37 (patch) | |
| tree | 4f3d976e4ab9dda0a2a7d31c19634b55b345c95f | |
| parent | b70a5cc045197aad9c159042621baf3c015f6cc7 (diff) | |
| download | linux-6bf536eb5c8ca011d1ff57b5c5f7c57ceac06a37.tar.xz | |
net/smc: correct settings of RMB window update limit
rmbe_update_limit is used to limit announcing receive
window updating too frequently. RFC7609 request a minimal
increase in the window size of 10% of the receive buffer
space. But current implementation used:
min_t(int, rmbe_size / 10, SOCK_MIN_SNDBUF / 2)
and SOCK_MIN_SNDBUF / 2 == 2304 Bytes, which is almost
always less then 10% of the receive buffer space.
This causes the receiver always sending CDC message to
update its consumer cursor when it consumes more then 2K
of data. And as a result, we may encounter something like
"TCP silly window syndrome" when sending 2.5~8K message.
This patch fixes this using max(rmbe_size / 10, SOCK_MIN_SNDBUF / 2).
With this patch and SMC autocorking enabled, qperf 2K/4K/8K
tcp_bw test shows 45%/75%/40% increase in throughput respectively.
Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/smc/smc_core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index 29525d03b253..1674b2549f8b 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1988,7 +1988,7 @@ static struct smc_buf_desc *smc_buf_get_slot(int compressed_bufsize, */ static inline int smc_rmb_wnd_update_limit(int rmbe_size) { - return min_t(int, rmbe_size / 10, SOCK_MIN_SNDBUF / 2); + return max_t(int, rmbe_size / 10, SOCK_MIN_SNDBUF / 2); } /* map an rmb buf to a link */ |