Re: FW: profiling

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

At 05:05 PM 2001-09-20, Howard Chu wrote:
>Has anyone spent any time profiling slapd to see where the CPU time goes?

It's been awhile since I have done any... but as I recall, primary
issues were in indexing and, in particular, management of IDLs.
Of course, kind of depends on whether all entries/indices are cached
or not and many other factors.

>I've been doing a bit of this; I've long believed that slapd is too
>malloc/free happy and needs some more efficient data structure approaches.

Heap allocation is certainly an area which takes significant time.
There are a number of areas where some improvements can be made.
In back-bdb, I've done some work to use stack allocated IDLs.
Unfornately, stack limitations in threading environments severely
limits the ability to shift large structures from the heap to the
stack with default thread settings.  I hadn't the time pursue this
further.

>Getting a decent profile is somewhat tricky.

Yes. Though there are a number of tricks, one trick I meant to
actually commit was an interrupt handler that used moncontrol(3)
to toggle on/off profiling... 

Kurt