Date: Sun, 20 Jan 2013 23:38:38 -0400 From: Karthik Reddy <22karthikreddy@gmail.com> To: Adam Vande More <amvandemore@gmail.com> Cc: freebsd-questions@freebsd.org Subject: Re: What is the timeout of TCP in freeBSD? Message-ID: <CALK7g0gtcN6rOUDskSuEnvS_qJuJLPjdqrUqO8v0d%2BSu_Lqj1g@mail.gmail.com> In-Reply-To: <CA%2BtpaK3mP06wt=3G5GYN8EV1pvYsn2Eq070Fuo-eHq_4UJExjw@mail.gmail.com> References: <CALK7g0h82SJSObmVo08z6=UAgB-ykc3QS4ApCAnkcvxbCdy5UA@mail.gmail.com> <CA%2BtpaK3mP06wt=3G5GYN8EV1pvYsn2Eq070Fuo-eHq_4UJExjw@mail.gmail.com>
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When I change the kern.hz to 50, the timeout is happening at 76sec. Could you please elaborate on kern.hz and how does it effect timing. On Sun, Jan 20, 2013 at 10:12 PM, Adam Vande More <amvandemore@gmail.com>wrote: > On Sun, Jan 20, 2013 at 8:50 AM, Karthik Reddy <22karthikreddy@gmail.com>wrote: > >> I was doing a experiment on FreeBSD for testing TCP timeout and RTO. OS is >> being run from two different VMware versions 4.0 and 5.0. >> >> Present Scenario: VMware Player 4.0 >> I'll start a telnet session to a non-existing system in the network. When >> I >> look at the tcpdump the RTO starts at every 3 seconds and after some >> exponential backoff starts. In this scenario after 75 seconds the TCP >> gives >> up and tells me that there is no system existing with the IP and telnet >> session terminates. >> >> Next Scenario: VMware Player 5.0 >> In this scenario, I did the same but the RTO starts at 5 sec and then >> varies. In this scenario, it takes more than 120 seconds for telnet >> session >> to tell me that there is no system is available in the network. >> >> I have seen sysctl in both VM's. net.inet.tcp.keepinit = 75000 >> >> Is this problem something related to timing of the VM's or any other >> issue? >> > > What's the wallclock delta during such a test? Have you tried setting > 'kern.hz="50"' or fiddling other TC options? UP VM's tend to keep time > better than other multicore configs. > > -- > Adam Vande More -- Karthik Reddy I'm not the best, but I'm not like the Rest
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