Date: Thu, 16 Jun 2005 06:14:54 -0500 From: Eric Anderson <anderson@centtech.com> To: "M. Warner Losh" <imp@bsdimp.com> Cc: freebsd-current@freebsd.org, jeremie@le-hen.org Subject: Re: incorrect ping(8) interval with powerd(8) Message-ID: <42B15F2E.9050408@centtech.com> In-Reply-To: <20050616.020442.31252848.imp@bsdimp.com> References: <20050616070445.GD2239@obiwan.tataz.chchile.org> <20050616.012302.48201645.imp@bsdimp.com> <20050616075743.GE2239@obiwan.tataz.chchile.org> <20050616.020442.31252848.imp@bsdimp.com>
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M. Warner Losh wrote: > In message: <20050616075743.GE2239@obiwan.tataz.chchile.org> > Jeremie Le Hen <jeremie@le-hen.org> writes: > : > : May you delve into this a little bit more please ? The ping(8) manual > : > : page states that the -i flags makes ping(8) to wait a given couple of > : > : seconds. If I use the flags "-i 1", I expect ECHO Requests to be sent > : > : with one second between each, whatever the AC line status is. > : > : (Note that I didn't explicitely specified "-i 1" in the above example, > : > : but this doesn't change the behaviour.) > : > > : > Well, the rount trip times went way up (3x longer). That's normal for > : > a 200MHz CPU... My 333MHz EISA machine can't do much better than > : > that. > : > > : > But the 2.252s run time is a little longish. Do you see this > : > consistantly? If you ran it a second time would you get identical > : > results. I've seen ARP take a while... What else do you have running > : > on the system? Maybe a daemon that takes almost no time at 1.7GHz > : > takes a lot longer at 200Mhz and that's starving the ping process... > : > Or some driver has gone insane... > : > : Yes, I ran this test multiple times, and I almost get always this same > : result although I got 2.208s sometimes, but I don't think this is > : significant. > : > : FYI, > : my powerd(8) is configured to tastes AC-line four times per seconds. > : I tried reducing it's freqency from 4 to 1, but it doesn't change > : anything. > : > : ARP is not the culprit, the MAC address is already in cache. > : > : My kernel is compiled with INVARIANTS, but I don't have WITNESS. My > : network interface uses the bge(4) driver. No firewall rule or complex > : network setup. > : > : Anyway this doesn't hurt much. Thanks for lightening me. > > Dang, I was hoping it was one of the easy explainations.... Maybe it > is the idle code not waking up fast enough when it has been asleep for > a bit. But that's pure speculation at this point... Another datapoint - running -CURRENT as of about June 7th, I see this too: $ time ping -i 1 -c 5 localhost PING localhost (127.0.0.1): 56 data bytes 64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.041 ms 64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.033 ms 64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.029 ms 64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.031 ms 64 bytes from 127.0.0.1: icmp_seq=4 ttl=64 time=0.035 ms --- localhost ping statistics --- 5 packets transmitted, 5 packets received, 0% packet loss round-trip min/avg/max/stddev = 0.029/0.034/0.041/0.004 ms real 0m9.728s user 0m0.000s sys 0m0.003s On a 5-STABLE machine: $ time ping -i 1 -c 5 localhost PING localhost (127.0.0.1): 56 data bytes 64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.049 ms 64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.032 ms 64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.024 ms 64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.021 ms 64 bytes from 127.0.0.1: icmp_seq=4 ttl=64 time=0.032 ms --- localhost ping statistics --- 5 packets transmitted, 5 packets received, 0% packet loss round-trip min/avg/max/stddev = 0.021/0.032/0.049/0.010 ms real 0m4.064s user 0m0.000s sys 0m0.005s I have powerd running, but it makes no difference whether I have it running or not, nor does it make any difference if I'm on ac or battery. This worked fine a couple weeks back for me - the only thing I recall changing is adding apic to my kernel. Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology A lost ounce of gold may be found, a lost moment of time never. ------------------------------------------------------------------------
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