: Use MSS for larger initial windows
Subsystems (2)
PATCH 17/31 : Use MSS for larger initial windows
This improves the slow-start phase by using the MSS (as suggested in RFC 4342, sec. 5) instead of the packet size s. Also figured out that __u32 is ample resource enough.
After applying, I got the following in the logs:
ccid3_hc_tx_packet_recv: client(f7421700), s=6, MSS=1424, w_init=4380, R_sample=176us, X=24886363
Had the previous variant been used, w_init would have been as low as 24.
Committer note: removed unneeded cast to unsigned long long that was
causing a compiler warning on 64bit architectures.
Signed-off-by Gerrit Renker <[email protected]>
Acked-by Ian McDonald <[email protected]>
Signed-off-by Arnaldo Carvalho de Melo <[email protected]>
--- net/dccp/ccids/ccid3.c | 10 +++++----- 1 files changed, 5 insertions(+), 5 deletions(-)
net/dccp/ccids/ccid3.c +5 -5
@@ -466,20 +466,20 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)if (hctx->ccid3hctx_state ==TFRC_SSTATE_NO_FBACK ) {/* * Larger Initial Windows [RFC 4342, sec. 5] -* We deviate in that we use `s' instead of `MSS'. */ -__u64 w_init =min (4 * hctx->ccid3hctx_s, -max (2 * hctx->ccid3hctx_s,4380 )); +__u32 w_init =min (4 * dp->dccps_mss_cache, +max (2 * dp->dccps_mss_cache,4380U )); hctx->ccid3hctx_rtt = r_sample; hctx->ccid3hctx_x =scaled_div (w_init <<6 , r_sample); hctx->ccid3hctx_t_ld = now;ccid3_update_send_time (hctx); -ccid3_pr_debug ("%s(%p), s=%u, w_init=%llu, " +ccid3_pr_debug ("%s(%p), s=%u, MSS=%u, w_init=%u, " "R_sample=%dus, X=%u\n" ,dccp_role (sk), sk, hctx->ccid3hctx_s, - (unsigned long long )w_init, + dp->dccps_mss_cache, + w_init, (int )r_sample, (unsigned )(hctx->ccid3hctx_x >>6 ));
Signature · 1 line
1.5.0.3