[nSLUG] httpd busy on idle machine?

D G Teed donald.teed at gmail.com
Sun Jun 28 16:36:44 ADT 2015


On Thu, Jun 25, 2015 at 9:15 AM, Hatem Nassrat <hnassrat at gmail.com> wrote:
>
>> On Jun 25, 2015 3:49 AM, "Mike Spencer" <mspencer at tallships.ca> wrote:
>> >
>> > root shows a steady stream of this:
>> >
>> >    select(0, NULL, NULL, NULL, {1, 0})    = 0 (Timeout)
>> >    waitpid(-1, 0xfbb9934, WNOHANG|WSTOPPED) = 0
>> >
>> > about 1 per second.
>> >
>> > Trace of some instances that belong to apache seem to be doing nothing
>> > but some are furiously busy:
>> >
>> >     gettimeofday({1435211835, 144305}, NULL) = 0
>> >     gettimeofday({1435211835, nnnnnn}, NULL) = 0
>> >     gettimeofday({1435211835, nnnnnn}, NULL) = 0
>> >     epoll_wait(7, {}, 25, 100)
>> >
>> > repeated very rapidly; where nnnnnn is a 6 digit number, different in
>> > each line.  (htop seems to disable the X copy/paste function in an
>> > xterm so I have to type data from htop.)
>>
>> I believe these two entries are your answer.
>>
>> The first seems to indicate a busy wait on a socket with a 1 sec timeout.
>>
>> The second indicates that apache is asking for the time of day perhaps for
>> use in a log file would be my guess?
>>
>> I might have missed it, but did you check the apache error log files as
>> well as syslog to see if there is any activity there? Perhaps even the
>> access log files but my guess is you prob wont see anything there.

I have not tried it yet, but at the end of the work day I was looking at
an article about using sysdig.

http://www.sysdig.org/

It looks very good, just a lot of verbose syntax, which seems to be the
way things are going with systemd, ldap, ipv6, etc.


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