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authorDust Li <dust.li@linux.alibaba.com>2022-03-01 17:44:00 +0800
committerDavid S. Miller <davem@davemloft.net>2022-03-01 14:25:12 +0000
commit6bf536eb5c8ca011d1ff57b5c5f7c57ceac06a37 (patch)
tree4f3d976e4ab9dda0a2a7d31c19634b55b345c95f /net/smc
parentb70a5cc045197aad9c159042621baf3c015f6cc7 (diff)
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>
Diffstat (limited to 'net/smc')
-rw-r--r--net/smc/smc_core.c2
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 */