On 16. juli. 2009, at 12.15, Mike Lambert wrote:
Incidentally, why was "mallinfo" removed from memcache 1.4.0? Even
without it being 64-bit aware, it still provided some useful data that
I wasn't able to get via other means in our 1.2.6 binaries.
I wanted to remove the mallinfo call from memcached because I don't
think it belongs in the memcached protocol, but this is something you
can get from other tools (like pmap).
Another problem with using mallinfo is that not all memory allocators
implements mallinfo. By checking for mallinfo in configure (at least
on Solaris) would cause memcached to link with libmalloc, and if you
look at the manual page for libmalloc you will find:
DESCRIPTION
Functions in this library provide routines for memory allo-
cation. These routines are space-efficient but have lower
performance. Their usage can result in serious performance
degradation.
You may think that this wouldn't be a problem because we use our own
memory allocator inside memcached, but that's not true. The slab
allocator is _only_ used to store the items, and all other memory
allocations is done through malloc (hash tables, connection structs
and buffers, suffix pool etc).
Cheers,
Trond
