[Dovecot] FreeBSD 6.1-RELEASE/kqueue high CPU load

[LI Xin]

Taras Savchuk wrote:
[snip]
>> What if you get some output from ktrace/kdump?  Additionally, try to
>> force the process to save a coredump and investigate its .core with gdb
>> would help tracking down the issue...
>>
>> Note that because when using kqueue the process should get a "kqread" if
>> it is waiting for kqueue event.  If the process is stuck in "RUN" state
>> then a coredump would be more helpful.
>>
>> Cheers,
>>   
> ~20000 calls to gettimeofday() per second. Is it normall?

No!  What's more, gettimeofday() is much more expensive on FreeBSD than
its Linux counterpart, as it provides higher resolution time which is
not useful for many applications.

My guess is that your imap instance is stuck in a state where either
kevent() is called with a zero ts structure (which is effectively a
poll) every time, or some other weird thing happend.

> mail2# cat k.dov.l.txt | grep CALL | grep gettimeofday | wc -l
> 1195552
> mail2# head -n 1 k.dov.l.txt
> 20910 imap 0.000000 CALL gettimeofday(0x80c2c60,0x80c2c68)
> mail2# tail -n 1 k.dov.l.txt
> 20910 imap 51.826065 RET gettimeofday 0

Are these gettimeofday() calls called one by one?  Or is there any other
calls between gettimeofday's?

Cheers,
-- 
Xin LI <delphij at delphij.net>	http://www.delphij.net/
FreeBSD - The Power to Serve!

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