ocstat

[Aggelos Economopoulos]

On Wednesday 04 June 2008, Nicolas Thery wrote:
> Hello,
> 
> As part of my quest of migrating zones allocations to kmalloc/objcache,
> I'm writing a small utility that dumps stats about each object cache.
> 
> By default, it displays (from left to right), the cache name, magazine capacity
> (MAGC), number of unallocated objects (UNOBJ), number of empty (EMAG)
> and full magazines (FMAG) in the depot, number of objects in loaded (LRD)
> and previous (PRD) rounds.  Per-cpu values are separated by commas:
[...]
> It also provides the number of successful gets and puts and failed
> gets since boot:
[...]
> There is also a -l option to display all available stats and a -o one
> to select what
> fields to display (a la ps(1)).
> 
> Internally, I added an opaque sysctl to objcache that dumps all stats and is
> parsed by ocstat.
> 
> Do you think this could be added to base?  If so, I'll clean up the code
> and email patches here.

Should be useful. A thing that afaict is lacking from objectcache at the
moment is a debug mode; I've spend 1+ day chasing a bug that was caused by
a very subtle double free for an mbuf and the way I did it (add kprintf()s
for every mbuf malloc/free, also logging their call sites and write script
to track alloc/frees) cannot be reused. If kmalloc/kfree can detect stuff
like that we could add an option that makes objcache pass through all gets
and puts. Ideas?

Aggelos