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authorEric Dumazet <edumazet@google.com>2018-10-15 19:37:52 +0300
committerDavid S. Miller <davem@davemloft.net>2018-10-16 08:56:41 +0300
commit5f6188a8003d080e3753b8f14f4a5a2325ae1ff6 (patch)
tree17f35c12eeef92a69902b197a73c1123eaac9e63 /include/linux/tcp.h
parent1a3aea2534f4f3083f29b2b047aa83a9d6c777a4 (diff)
downloadlinux-5f6188a8003d080e3753b8f14f4a5a2325ae1ff6.tar.xz
tcp: do not change tcp_wstamp_ns in tcp_mstamp_refresh
In EDT design, I made the mistake of using tcp_wstamp_ns to store the last tcp_clock_ns() sample and to store the pacing virtual timer. This causes major regressions at high speed flows. Introduce tcp_clock_cache to store last tcp_clock_ns(). This is needed because some arches have slow high-resolution kernel time service. tcp_wstamp_ns is only updated when a packet is sent. Note that we can remove tcp_mstamp in the future since tcp_mstamp is essentially tcp_clock_cache/1000, so the apparent socket size increase is temporary. Fixes: 9799ccb0e984 ("tcp: add tcp_wstamp_ns socket field") Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/tcp.h')
-rw-r--r--include/linux/tcp.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 848f5b25e178..8ed77bb4ed86 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -249,6 +249,7 @@ struct tcp_sock {
u32 tlp_high_seq; /* snd_nxt at the time of TLP retransmit. */
u64 tcp_wstamp_ns; /* departure time for next sent data packet */
+ u64 tcp_clock_cache; /* cache last tcp_clock_ns() (see tcp_mstamp_refresh()) */
/* RTT measurement */
u64 tcp_mstamp; /* most recent packet received/sent */