Re: incorrect ping(8) interval with powerd(8)

Andre Guibert de Bruet wrote:
> 
> On Thu, 16 Jun 2005, Eric Anderson wrote:
> 
>> M. Warner Losh wrote:
>>
>>> In message: <20050616075743.GE2239_at_obiwan.tataz.chchile.org>
>>>             Jeremie Le Hen <jeremie_at_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.
> 
> 
> Just out of curiosity, does removing debugging options from your kernel 
> config change anything?

Nope.  And setting my scheduler back (from ULE) doesn't help either..

I'm thinking it must be a module, or something else I have installed.  I 
have set up another laptop just like mine, and it does not show the 
issue.  I'm still trying to track it down.


Eric



-- 
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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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