I wanted to determine if a change to malloc's behavior has any impact
on CPU usage. Tuning malloc was necessary because mod_brotli and glibc
appear to conspire on our systems to waste lots of memory due to heap
fragmentation (lowering MALLOC_ARENA_MAX and MALLOC_TRIM_THRESHOLD_
seems to help).
However, the "CPU Usage" stime and utime reported on mod_status's
ExtendedStatus page don't keep track of children that have died, for
example when MaxRequestsPerChild is reached. Therefore, one cannot
calculate an average by dividing those times by the number of Total
accesses.
There's a comment in mod_status.c that I believe refers to this:
/* XXX what about the counters for quiescing/seg faulted
* processes? should they be counted or not? GLA
*/
What's the intended meaning of the "CPU Usage" utime and stime
reported by mod_status?
We're using the worker MPM on CentOS 7.4, Ubuntu 17.10, 14.04 and Open
SuSE 42 with various versions of httpd.
rainer
