Hello,
I am doing some rough bench marking on some of my company's software on
a couple of different classes of alpha. Part of this process involves
running vmstat in the background while concurrent processes are running.
After all the processes have completed I take their log files and run them
past a log from vmstat to derive things like the number of process that
were running, and cpu and memory info at that point in time. From this
part of the test I hope to get an estimate of the cpu utilization from
the amount of idle time, and memory consumption from the rate of paging.
I am not particularly concerned with i/o performance here, as what I am
benchmarking has to do with in memory (mmap'd) table lookups
I went back in the list and read Tony Warner's "SUMMARY: memory
allocation" but I am looking for a bunch of parsible snapshots to graph
while the processes are busy doing their thing, not just one.
Summary from Evi Nemeth's "UNIX System Admin Handbook...
Memory Usage. There are basically two numbers that quantify memory
activity: the total amount of virtual memory ("act"), and the paging rate
("pin"). The total amount of virtual memory is an indication of the
total memory demand on a system. The paging is a reflection of what
portion of that memory is actively used.
My questions...
o "act" is all vm, I was hoping to get a snapshot of just "active
virtual memory". Since the inactive list has yet to be paged and
still could be saved, I would consider this OK to lump in, but
what about the Unified Buffer Cache (UBC). The man page states
that vmstat doesn't report on it, then under the section on "act"
it states that does. Which is it, anyone know?
o What's the best indicator of paging? "pin" seems to reflect the
activity more closely than anything else, but "react" (hard page
faults?) seems like the best indicator of memory consumption.
o In relating cpu utilization, I was planning on taking the ratio of
idle time to system time, but even on a nice fast 8400, idle
time seems to always be zero when you are running a bunch of
memory/cpu hungry processes. I am rethinking this to be a ratio of
(system_time/user_time); seems more interesting. Does this seem
like a valid measure?
Thanks for anybody's time,
Bryan
Received on Wed Jun 02 1999 - 12:59:13 NZST