Messages in this thread Patch in this message | | | Subject | Re: [net-next,v3] tcp: Improve setsockopt() TCP_USER_TIMEOUT accuracy | From | Eric Dumazet <> | Date | Tue, 10 Jul 2018 19:04:21 -0700 |
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On 07/10/2018 05:33 PM, Jonathan Maxwell wrote: > On Tue, Jul 10, 2018 at 10:48 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: >> >> >> On 07/10/2018 05:38 AM, Eric Dumazet wrote: >> >>> Note that if we always do jiffies_to_msecs(icsk->icsk_user_timeout) in TCP, >>> we also could change the convention and store msecs in this field instead of jiffies. >>> >>> That would eliminate the msecs_to_jiffies() and jiffies_to_msecs() dance. >>> >>> (That would be done in a patch of its own, of course) >> >> tcp_keepalive_timer() does use icsk->icsk_user_timeout directly in jiffies unit, >> but considering keeapalive timers are rarely used, this point would have to >> do the msecs_to_jiffies() conversion. > > and also if icsk->icsk_user_timeout = 0, then timeout in retransmits_timed_out() > is in jiffies and that would need to addressed.
Absolutely, this is what I was suggesting.
Pseudo code for this part, before your changes.
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 3b3611729928f77934e0298bb248e55c7a7c5def..cae7bbc956ed51e9d381650957f54550cc0967d9 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -183,8 +183,9 @@ static bool retransmits_timed_out(struct sock *sk, else timeout = ((2 << linear_backoff_thresh) - 1) * rto_base + (boundary - linear_backoff_thresh) * TCP_RTO_MAX; + timeout = jiffies_to_msecs(timeout)' } - return (tcp_time_stamp(tcp_sk(sk)) - start_ts) >= jiffies_to_msecs(timeout); + return (tcp_time_stamp(tcp_sk(sk)) - start_ts) >= timeout; } /* A write timeout has occurred. Process the after effects. */
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