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authorEric Dumazet <edumazet@google.com>2017-05-17 00:00:14 +0300
committerDavid S. Miller <davem@davemloft.net>2017-05-17 23:06:01 +0300
commit9a568de4818dea9a05af141046bd3e589245ab83 (patch)
tree6f1502edf55ecb7205660d62bd683ebcf912cfea /net/netfilter
parentac9517fcf310327fa3e3b0d8366e4b11236b1b4b (diff)
downloadlinux-9a568de4818dea9a05af141046bd3e589245ab83.tar.xz
tcp: switch TCP TS option (RFC 7323) to 1ms clock
TCP Timestamps option is defined in RFC 7323 Traditionally on linux, it has been tied to the internal 'jiffies' variable, because it had been a cheap and good enough generator. For TCP flows on the Internet, 1 ms resolution would be much better than 4ms or 10ms (HZ=250 or HZ=100 respectively) For TCP flows in the DC, Google has used usec resolution for more than two years with great success [1] Receive size autotuning (DRS) is indeed more precise and converges faster to optimal window size. This patch converts tp->tcp_mstamp to a plain u64 value storing a 1 usec TCP clock. This choice will allow us to upstream the 1 usec TS option as discussed in IETF 97. [1] https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-tcp-options-for-low-latency-00.pdf 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 'net/netfilter')
-rw-r--r--net/netfilter/nf_synproxy_core.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/netfilter/nf_synproxy_core.c b/net/netfilter/nf_synproxy_core.c
index a504e87c6ddf..49bd8bb16b18 100644
--- a/net/netfilter/nf_synproxy_core.c
+++ b/net/netfilter/nf_synproxy_core.c
@@ -152,7 +152,7 @@ void synproxy_init_timestamp_cookie(const struct xt_synproxy_info *info,
struct synproxy_options *opts)
{
opts->tsecr = opts->tsval;
- opts->tsval = tcp_time_stamp & ~0x3f;
+ opts->tsval = tcp_time_stamp_raw() & ~0x3f;
if (opts->options & XT_SYNPROXY_OPT_WSCALE) {
opts->tsval |= opts->wscale;