Admins,
Man, I love this board, within minutes help was one the way.
The first response was from John Francini:
... The shared memory segments will be charged against each
process' address space total, even though there's only one copy in
memory at any one time....
Seconds later Dr Blinn states...
Resident set size is the number of pages in the process' address space
that are in physical memory. It doesn't separate out process private
pages from shared pages; for example, all of the pages in libc that are
shared by active processes are counted in EVERY process address space
for processes that map libc. There are undoubtedly some UNIX systems
where it's easy to identify a page as "belonging" uniquely to one of
the active processes; Tru64 UNIX isn't one of them. In fact, pages in
files that are mapped into a process' address space count against RSS
if they are in memory (they count against VSS also, whether they are
in memory or not -- as you have probably already guessed).
Use "vmstat -P" and look at the managed page count. It's about as close
as you'll get to a breakdown of how the physical memory that's not just
owned by the kernel or the console is being used. But you still need to
have a pretty sound understanding of how Tru64 UNIX memory management
really works (and it's not well described any place I've found) to get
a real handle on what it all means.
Then as I finished Dr Blinn response Bryan Williams also confirmed the above...
Thanks to all above.
This answers my question in full. My original exploration was on free memory
shortage. Through out the day I maintain a free memory value around 1000 pages.
Sometimes this dips below 100 pages. I see no evidence of swapping but I have
an average of around 8 pages a second paged out during the peak. I haven't
determined if this is actually swapped out to disk or just to the buffer, but my
disk performance is doing well, So I was evaluating my process memory usage. I
have used vmstat -P in the past and it has helped, but I was hoping for a more
detailed answer. I think the box is set to high for its UBC upper percentage.
It was originally set to 100 percent since then I lowered it 90. I plan to
continue until I see other metrics effected. Thanks again for everyone support
Received on Mon May 14 2001 - 18:54:06 NZST