Memory Leak

[Nobody's Hero]

Hello All,

I have a small memory leak on an older K360.
I've pinned the problem to a resource map (rmap) overflow due to the ability to use 'Super Pages', OK. OK. I'm going to tune the kernel first and monitor the situation with an unsupported script from HP. If problem continues, I'll install a series of patches to fix this 10.20 bug, but my kern parms seem low, so I'll try that first. Well, my question is, what are 'Super Pages???? You can verify if you are using this by :::

echo cpu_has_var_size_pages/D | adb /stand/vmunix /dev/kmem

return of 1 = yes
return of 0 = no

Thanks in Advance (as always)
Bob Menefee

[harry d brown jr · Accepted solution]

http://citeseer.nj.nec.com/cache/papers/cs/19889/ftp:zSzzSzftp.cse.unsw.edu.auzSzpubzSzuserszSzdisyzSzug-theseszSz99-cls.pdf/szmajda99new.pdf

1.5 Super-pages
Common page sizes are 512 bytes (Atlas, VAX-11/780), 4kB (Intel 386), and 8kB (Alpha). The choice of page size is a space-time trade off. Larger pages require fewer translations and increase the overage
of the TLB (discussed later), but smaller pages increase the amount of memory that can be saved through demand-paging.

Newer architectures, such as the Intel Pentium [15] and MIPS R4000 [22], allow more than one page
size to co-exist in the same address space. The larger pages, called super-pages, have until recently
been used by operating systems only for specialized purposes, such as for mapping frame buffers or for kernel's own memory. Support for super-pages have the potential to reduce the frequency of TLB misses, since the coverage of the TLB is increased. This benefit is most noticeable in architectures where the TLB is refilled by software, and where each TLB entry is tagged with an address space ID, so that TLB entries survive an address space switch.

The addition of super-page support can increase the overall performance of applications by as much as
20% [33].


live free or die
harry

[Nobody's Hero]

Thanks,

That warrants a 10

[Frank Slootweg]

Harry gave a general answer.

For the HP-UX aspects, see the section "Performance-Optimized Page Sizing (POPS)" in the Release Notes for HP-UX 11.0 (/usr/share/doc/11.00RelNotes).