* Is keepalive behaving as expected in 3.7.0+/net-next?
@ 2012-12-21 22:05 Rick Jones
2012-12-27 21:54 ` Eric Dumazet
0 siblings, 1 reply; 6+ messages in thread
From: Rick Jones @ 2012-12-21 22:05 UTC (permalink / raw)
To: netdev
I was looking to do a bit more documentation clean-up and thought I
would work on the descriptions of the "keepalive" sysctls, but first I
wanted to see if they behaved as the existing descriptions suggested:
> tcp_keepalive_time - INTEGER
> How often TCP sends out keepalive messages when keepalive is enabled.
> Default: 2hours.
>
> tcp_keepalive_probes - INTEGER
> How many keepalive probes TCP sends out, until it decides that the
> connection is broken. Default value: 9.
>
> tcp_keepalive_intvl - INTEGER
> How frequently the probes are send out. Multiplied by
> tcp_keepalive_probes it is time to kill not responding connection,
> after probes started. Default value: 75sec i.e. connection
> will be aborted after ~11 minutes of retries.
I interpreted all that that as: When a connection is idle, TCP will
send a keepalive probe every tcp_keepalive_time seconds. If a response
to a keepalive probe is not received, TCP will resend (retransmit) it
every tcp_keepalive_intvl seconds.
However, what I see is that on a connection where the remote is indeed
still there, only the first keepalive probe is sent after
tcp_keepalive_time, and thereafter it is sent every tcp_keepalive_intvl
seconds.
Now, some of this may relate to my being impatient - rather than wait
two hours for the first probe, I set tcp_keepalive_time to 3 seconds,
and tcp_keepalive_intvl to 7 seconds. I then kicked-off a ./configure
--intervals-enable netperf TCP_RR test with a burst of one and a wait
time of 90 seconds and got the following (trimmed) trace:
13:43:46.879133 IP netnextraj.43054 > netnextraj2.srvr: Flags [S], seq
807869796, win 14600, options [mss 1460,sackOK,TS val 133470 ecr
0,nop,wscale 7], length 0
13:43:46.880091 IP netnextraj2.srvr > netnextraj.43054: Flags [S.], seq
1522345902, ack 807869797, win 14480, options [mss 1460,sackOK,TS val
136186 ecr 133470,nop,wscale 4], length 0
13:43:46.880114 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack
1, win 115, options [nop,nop,TS val 133470 ecr 136186], length 0
13:43:46.880306 IP netnextraj.43054 > netnextraj2.srvr: Flags [P.], seq
1:11, ack 1, win 115, options [nop,nop,TS val 133470 ecr 136186], length 10
13:43:46.880948 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack
11, win 905, options [nop,nop,TS val 136187 ecr 133470], length 0
13:43:46.880964 IP netnextraj2.srvr > netnextraj.43054: Flags [P.], seq
1:11, ack 11, win 905, options [nop,nop,TS val 136187 ecr 133470], length 10
13:43:46.881161 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack
11, win 115, options [nop,nop,TS val 133470 ecr 136187], length 0
The first probe above comes after 3 seconds - tcp_keepalive_time - at
13:43:49
13:43:49.886752 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack
11, win 115, options [nop,nop,TS val 134222 ecr 136187], length 0
And it does seem to elicit a response:
13:43:49.887530 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack
11, win 905, options [nop,nop,TS val 136938 ecr 133470], length 0
Now it starts sending probes every 7 seconds (tcp_keepalive_intvl):
13:43:56.903576 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack
11, win 115, options [nop,nop,TS val 135976 ecr 136938], length 0
13:43:56.904480 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack
11, win 905, options [nop,nop,TS val 138693 ecr 133470], length 0
13:44:03.910744 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack
11, win 115, options [nop,nop,TS val 137728 ecr 138693], length 0
13:44:03.911623 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack
11, win 905, options [nop,nop,TS val 140444 ecr 133470], length 0
I;ve deleted the next 9 or so probes... It continues, and doesn't
terminate the connection, so I assume it was happy with the responses to
the probes.
13:45:13.990746 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack
11, win 115, options [nop,nop,TS val 155248 ecr 156213], length 0
13:45:13.991578 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack
11, win 905, options [nop,nop,TS val 157965 ecr 133470], length 0
Now the next netperf transaction happens:
13:45:16.879222 IP netnextraj.43054 > netnextraj2.srvr: Flags [P.], seq
11:21, ack 11, win 115, options [nop,nop,TS val 155970 ecr 157965],
length 10
13:45:16.880033 IP netnextraj2.srvr > netnextraj.43054: Flags [P.], seq
11:21, ack 21, win 905, options [nop,nop,TS val 158687 ecr 155970],
length 10
13:45:16.880220 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack
21, win 115, options [nop,nop,TS val 155970 ecr 158687], length 0
But the next keepalive probe is tcp_keepalive_intvl seconds after the
last one, rather than that many, or tcp_keepalive_time seconds after the
connection was last "active."
13:45:20.998739 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack
21, win 115, options [nop,nop,TS val 157000 ecr 158687], length 0
13:45:20.999754 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack
21, win 905, options [nop,nop,TS val 159717 ecr 155970], length 0
13:45:28.006747 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack
21, win 115, options [nop,nop,TS val 158752 ecr 159717], length 0
13:45:28.007624 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack
21, win 905, options [nop,nop,TS val 161469 ecr 155970], length 0
Is this the expected behaviour? If I reverse the values - make
tcp_keepalive_time 7 and tcp_keepalive_intvl 3, it seems that all the
probes are after 7 seconds.
rick jones
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Is keepalive behaving as expected in 3.7.0+/net-next? 2012-12-21 22:05 Is keepalive behaving as expected in 3.7.0+/net-next? Rick Jones @ 2012-12-27 21:54 ` Eric Dumazet 2012-12-29 19:47 ` Jamie Gloudon 0 siblings, 1 reply; 6+ messages in thread From: Eric Dumazet @ 2012-12-27 21:54 UTC (permalink / raw) To: Rick Jones; +Cc: netdev, Jamie Gloudon On Fri, 2012-12-21 at 14:05 -0800, Rick Jones wrote: > I was looking to do a bit more documentation clean-up and thought I > would work on the descriptions of the "keepalive" sysctls, but first I > wanted to see if they behaved as the existing descriptions suggested: > > > tcp_keepalive_time - INTEGER > > How often TCP sends out keepalive messages when keepalive is enabled. > > Default: 2hours. > > > > tcp_keepalive_probes - INTEGER > > How many keepalive probes TCP sends out, until it decides that the > > connection is broken. Default value: 9. > > > > tcp_keepalive_intvl - INTEGER > > How frequently the probes are send out. Multiplied by > > tcp_keepalive_probes it is time to kill not responding connection, > > after probes started. Default value: 75sec i.e. connection > > will be aborted after ~11 minutes of retries. > > I interpreted all that that as: When a connection is idle, TCP will > send a keepalive probe every tcp_keepalive_time seconds. If a response > to a keepalive probe is not received, TCP will resend (retransmit) it > every tcp_keepalive_intvl seconds. > > However, what I see is that on a connection where the remote is indeed > still there, only the first keepalive probe is sent after > tcp_keepalive_time, and thereafter it is sent every tcp_keepalive_intvl > seconds. > > Now, some of this may relate to my being impatient - rather than wait > two hours for the first probe, I set tcp_keepalive_time to 3 seconds, > and tcp_keepalive_intvl to 7 seconds. I then kicked-off a ./configure > --intervals-enable netperf TCP_RR test with a burst of one and a wait > time of 90 seconds and got the following (trimmed) trace: > > 13:43:46.879133 IP netnextraj.43054 > netnextraj2.srvr: Flags [S], seq > 807869796, win 14600, options [mss 1460,sackOK,TS val 133470 ecr > 0,nop,wscale 7], length 0 > 13:43:46.880091 IP netnextraj2.srvr > netnextraj.43054: Flags [S.], seq > 1522345902, ack 807869797, win 14480, options [mss 1460,sackOK,TS val > 136186 ecr 133470,nop,wscale 4], length 0 > 13:43:46.880114 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > 1, win 115, options [nop,nop,TS val 133470 ecr 136186], length 0 > 13:43:46.880306 IP netnextraj.43054 > netnextraj2.srvr: Flags [P.], seq > 1:11, ack 1, win 115, options [nop,nop,TS val 133470 ecr 136186], length 10 > 13:43:46.880948 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > 11, win 905, options [nop,nop,TS val 136187 ecr 133470], length 0 > 13:43:46.880964 IP netnextraj2.srvr > netnextraj.43054: Flags [P.], seq > 1:11, ack 11, win 905, options [nop,nop,TS val 136187 ecr 133470], length 10 > 13:43:46.881161 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > 11, win 115, options [nop,nop,TS val 133470 ecr 136187], length 0 > > The first probe above comes after 3 seconds - tcp_keepalive_time - at > 13:43:49 > > 13:43:49.886752 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > 11, win 115, options [nop,nop,TS val 134222 ecr 136187], length 0 > > And it does seem to elicit a response: > > 13:43:49.887530 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > 11, win 905, options [nop,nop,TS val 136938 ecr 133470], length 0 > > Now it starts sending probes every 7 seconds (tcp_keepalive_intvl): > > 13:43:56.903576 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > 11, win 115, options [nop,nop,TS val 135976 ecr 136938], length 0 > 13:43:56.904480 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > 11, win 905, options [nop,nop,TS val 138693 ecr 133470], length 0 > 13:44:03.910744 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > 11, win 115, options [nop,nop,TS val 137728 ecr 138693], length 0 > 13:44:03.911623 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > 11, win 905, options [nop,nop,TS val 140444 ecr 133470], length 0 > > I;ve deleted the next 9 or so probes... It continues, and doesn't > terminate the connection, so I assume it was happy with the responses to > the probes. > > 13:45:13.990746 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > 11, win 115, options [nop,nop,TS val 155248 ecr 156213], length 0 > 13:45:13.991578 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > 11, win 905, options [nop,nop,TS val 157965 ecr 133470], length 0 > > Now the next netperf transaction happens: > > 13:45:16.879222 IP netnextraj.43054 > netnextraj2.srvr: Flags [P.], seq > 11:21, ack 11, win 115, options [nop,nop,TS val 155970 ecr 157965], > length 10 > 13:45:16.880033 IP netnextraj2.srvr > netnextraj.43054: Flags [P.], seq > 11:21, ack 21, win 905, options [nop,nop,TS val 158687 ecr 155970], > length 10 > 13:45:16.880220 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > 21, win 115, options [nop,nop,TS val 155970 ecr 158687], length 0 > > But the next keepalive probe is tcp_keepalive_intvl seconds after the > last one, rather than that many, or tcp_keepalive_time seconds after the > connection was last "active." > > 13:45:20.998739 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > 21, win 115, options [nop,nop,TS val 157000 ecr 158687], length 0 > 13:45:20.999754 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > 21, win 905, options [nop,nop,TS val 159717 ecr 155970], length 0 > 13:45:28.006747 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > 21, win 115, options [nop,nop,TS val 158752 ecr 159717], length 0 > 13:45:28.007624 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > 21, win 905, options [nop,nop,TS val 161469 ecr 155970], length 0 > > Is this the expected behaviour? If I reverse the values - make > tcp_keepalive_time 7 and tcp_keepalive_intvl 3, it seems that all the > probes are after 7 seconds. > > rick jones Not sure if it makes sense to have tcp_keepalive_intvl > tcp_keepalive_time time should be an order of magnitude bigger than intvl. keepalive timer is not reset each time we receive a valid frame, it would be very expensive. Its a long period timer. First interval is tcp_keepalive_time, and subsequent interval are tcp_keepalive_intvl Each time timer is fired (once every 7200 seconds), we re-arm it with the observed elapsed time (keepalive_time_elapsed) Fixing this would require to add a timestamp in inet socket, to remember time of next/last probe, and firing the timer using min(keepalive_time_when(tp), keepalive_intvl_when(tp)) Probably not worth it. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Is keepalive behaving as expected in 3.7.0+/net-next? 2012-12-27 21:54 ` Eric Dumazet @ 2012-12-29 19:47 ` Jamie Gloudon 2012-12-30 20:51 ` Rick Jones 0 siblings, 1 reply; 6+ messages in thread From: Jamie Gloudon @ 2012-12-29 19:47 UTC (permalink / raw) To: Eric Dumazet; +Cc: rick.jones2, netdev On Thu, Dec 27, 2012 at 01:54:25PM -0800, Eric Dumazet wrote: > On Fri, 2012-12-21 at 14:05 -0800, Rick Jones wrote: > > I was looking to do a bit more documentation clean-up and thought I > > would work on the descriptions of the "keepalive" sysctls, but first I > > wanted to see if they behaved as the existing descriptions suggested: > > > > > tcp_keepalive_time - INTEGER > > > How often TCP sends out keepalive messages when keepalive is enabled. > > > Default: 2hours. > > > > > > tcp_keepalive_probes - INTEGER > > > How many keepalive probes TCP sends out, until it decides that the > > > connection is broken. Default value: 9. > > > > > > tcp_keepalive_intvl - INTEGER > > > How frequently the probes are send out. Multiplied by > > > tcp_keepalive_probes it is time to kill not responding connection, > > > after probes started. Default value: 75sec i.e. connection > > > will be aborted after ~11 minutes of retries. > > > > I interpreted all that that as: When a connection is idle, TCP will > > send a keepalive probe every tcp_keepalive_time seconds. If a response > > to a keepalive probe is not received, TCP will resend (retransmit) it > > every tcp_keepalive_intvl seconds. > > > > However, what I see is that on a connection where the remote is indeed > > still there, only the first keepalive probe is sent after > > tcp_keepalive_time, and thereafter it is sent every tcp_keepalive_intvl > > seconds. > > > > Now, some of this may relate to my being impatient - rather than wait > > two hours for the first probe, I set tcp_keepalive_time to 3 seconds, > > and tcp_keepalive_intvl to 7 seconds. I then kicked-off a ./configure > > --intervals-enable netperf TCP_RR test with a burst of one and a wait > > time of 90 seconds and got the following (trimmed) trace: > > > > 13:43:46.879133 IP netnextraj.43054 > netnextraj2.srvr: Flags [S], seq > > 807869796, win 14600, options [mss 1460,sackOK,TS val 133470 ecr > > 0,nop,wscale 7], length 0 > > 13:43:46.880091 IP netnextraj2.srvr > netnextraj.43054: Flags [S.], seq > > 1522345902, ack 807869797, win 14480, options [mss 1460,sackOK,TS val > > 136186 ecr 133470,nop,wscale 4], length 0 > > 13:43:46.880114 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > > 1, win 115, options [nop,nop,TS val 133470 ecr 136186], length 0 > > 13:43:46.880306 IP netnextraj.43054 > netnextraj2.srvr: Flags [P.], seq > > 1:11, ack 1, win 115, options [nop,nop,TS val 133470 ecr 136186], length 10 > > 13:43:46.880948 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > > 11, win 905, options [nop,nop,TS val 136187 ecr 133470], length 0 > > 13:43:46.880964 IP netnextraj2.srvr > netnextraj.43054: Flags [P.], seq > > 1:11, ack 11, win 905, options [nop,nop,TS val 136187 ecr 133470], length 10 > > 13:43:46.881161 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > > 11, win 115, options [nop,nop,TS val 133470 ecr 136187], length 0 > > > > The first probe above comes after 3 seconds - tcp_keepalive_time - at > > 13:43:49 > > > > 13:43:49.886752 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > > 11, win 115, options [nop,nop,TS val 134222 ecr 136187], length 0 > > > > And it does seem to elicit a response: > > > > 13:43:49.887530 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > > 11, win 905, options [nop,nop,TS val 136938 ecr 133470], length 0 > > > > > > Now it starts sending probes every 7 seconds (tcp_keepalive_intvl): > > > > 13:43:56.903576 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > > 11, win 115, options [nop,nop,TS val 135976 ecr 136938], length 0 > > 13:43:56.904480 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > > 11, win 905, options [nop,nop,TS val 138693 ecr 133470], length 0 > > 13:44:03.910744 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > > 11, win 115, options [nop,nop,TS val 137728 ecr 138693], length 0 > > 13:44:03.911623 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > > 11, win 905, options [nop,nop,TS val 140444 ecr 133470], length 0 > > > > I;ve deleted the next 9 or so probes... It continues, and doesn't > > terminate the connection, so I assume it was happy with the responses to > > the probes. > > > > 13:45:13.990746 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > > 11, win 115, options [nop,nop,TS val 155248 ecr 156213], length 0 > > 13:45:13.991578 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > > 11, win 905, options [nop,nop,TS val 157965 ecr 133470], length 0 > > > > Now the next netperf transaction happens: > > > > 13:45:16.879222 IP netnextraj.43054 > netnextraj2.srvr: Flags [P.], seq > > 11:21, ack 11, win 115, options [nop,nop,TS val 155970 ecr 157965], > > length 10 > > 13:45:16.880033 IP netnextraj2.srvr > netnextraj.43054: Flags [P.], seq > > 11:21, ack 21, win 905, options [nop,nop,TS val 158687 ecr 155970], > > length 10 > > 13:45:16.880220 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > > 21, win 115, options [nop,nop,TS val 155970 ecr 158687], length 0 > > > > But the next keepalive probe is tcp_keepalive_intvl seconds after the > > last one, rather than that many, or tcp_keepalive_time seconds after the > > connection was last "active." > > > > 13:45:20.998739 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > > 21, win 115, options [nop,nop,TS val 157000 ecr 158687], length 0 > > 13:45:20.999754 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > > 21, win 905, options [nop,nop,TS val 159717 ecr 155970], length 0 > > 13:45:28.006747 IP netnextraj.43054 > netnextraj2.srvr: Flags [.], ack > > 21, win 115, options [nop,nop,TS val 158752 ecr 159717], length 0 > > 13:45:28.007624 IP netnextraj2.srvr > netnextraj.43054: Flags [.], ack > > 21, win 905, options [nop,nop,TS val 161469 ecr 155970], length 0 > > > > Is this the expected behaviour? If I reverse the values - make > > tcp_keepalive_time 7 and tcp_keepalive_intvl 3, it seems that all the > > probes are after 7 seconds. > > > > rick jones > > Not sure if it makes sense to have > tcp_keepalive_intvl > tcp_keepalive_time > > time should be an order of magnitude bigger than intvl. > > keepalive timer is not reset each time we receive a valid frame, it > would be very expensive. > > Its a long period timer. > > First interval is tcp_keepalive_time, and subsequent interval are > tcp_keepalive_intvl > > Each time timer is fired (once every 7200 seconds), we re-arm it with > the observed elapsed time (keepalive_time_elapsed) > > Fixing this would require to add a timestamp in inet socket, to remember > time of next/last probe, and firing the timer using > min(keepalive_time_when(tp), keepalive_intvl_when(tp)) > > Probably not worth it. > > Make a lot of sense. However, I got the impression from Rick that having tcp_keepalive_intvl > tcp_keepalive_time behaved correctly in older versions of the kernel. Regards, Jamie Gloudon ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Is keepalive behaving as expected in 3.7.0+/net-next? 2012-12-29 19:47 ` Jamie Gloudon @ 2012-12-30 20:51 ` Rick Jones 2012-12-31 1:50 ` Jamie Gloudon 0 siblings, 1 reply; 6+ messages in thread From: Rick Jones @ 2012-12-30 20:51 UTC (permalink / raw) To: Jamie Gloudon; +Cc: Eric Dumazet, netdev > Make a lot of sense. However, I got the impression from Rick that > having tcp_keepalive_intvl > tcp_keepalive_time behaved correctly in > older versions of the kernel. I seek to make no assertions about the behaviour of older kernels. I was just going off the ip-sysctl.txt wording I was looking to clean-up. rick ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Is keepalive behaving as expected in 3.7.0+/net-next? 2012-12-30 20:51 ` Rick Jones @ 2012-12-31 1:50 ` Jamie Gloudon 2013-01-03 20:13 ` Rick Jones 0 siblings, 1 reply; 6+ messages in thread From: Jamie Gloudon @ 2012-12-31 1:50 UTC (permalink / raw) To: Rick Jones; +Cc: Eric Dumazet, netdev On Sun, Dec 30, 2012 at 12:51:47PM -0800, Rick Jones wrote: > >Make a lot of sense. However, I got the impression from Rick that > >having tcp_keepalive_intvl > tcp_keepalive_time behaved correctly in > >older versions of the kernel. > > I seek to make no assertions about the behaviour of older kernels. I was > just going off the ip-sysctl.txt wording I was looking to clean-up. > > rick Ok, should ip-sysctl.txt documentation be updated to warn not to set tcp_keepalive_intvl > tcp_keepalive_time? Regards, Jamie Gloudon ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Is keepalive behaving as expected in 3.7.0+/net-next? 2012-12-31 1:50 ` Jamie Gloudon @ 2013-01-03 20:13 ` Rick Jones 0 siblings, 0 replies; 6+ messages in thread From: Rick Jones @ 2013-01-03 20:13 UTC (permalink / raw) To: Jamie Gloudon; +Cc: Eric Dumazet, netdev On 12/30/2012 05:50 PM, Jamie Gloudon wrote: > On Sun, Dec 30, 2012 at 12:51:47PM -0800, Rick Jones wrote: >>> Make a lot of sense. However, I got the impression from Rick that >>> having tcp_keepalive_intvl > tcp_keepalive_time behaved correctly in >>> older versions of the kernel. >> >> I seek to make no assertions about the behaviour of older kernels. I was >> just going off the ip-sysctl.txt wording I was looking to clean-up. >> >> rick > > Ok, should ip-sysctl.txt documentation be updated to warn not to set tcp_keepalive_intvl > tcp_keepalive_time? Well, that or explain how it will not always be the time interval at which the probes are sent. rick ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-01-03 20:13 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-12-21 22:05 Is keepalive behaving as expected in 3.7.0+/net-next? Rick Jones 2012-12-27 21:54 ` Eric Dumazet 2012-12-29 19:47 ` Jamie Gloudon 2012-12-30 20:51 ` Rick Jones 2012-12-31 1:50 ` Jamie Gloudon 2013-01-03 20:13 ` Rick Jones
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