Re: [PATCH] dtrace probes for memory manager

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> As far as I am concerned that is way too much, particularly
> considering that your test case isn't designed to be particularly
> memory-allocation intensive, and if it is up to me I will reject this.
> Even a quarter-percent slowdown for a feature that will be used only
> by a small fraction of users only a small fraction of time time seems
> totally unacceptable to me.

It seems to me that anyone who really needs this can instrument the
alloc functions anyway --- isn't one of the features of DTrace supposed
to be that you can monitor calls to a particular function without any
prearranged code support? Or is that one of the things like "zero
overhead" that turns out to be more marketing-speak than reality?

Anyway I concur with Robert's opinion that the use-case is far too small
to justify incurring a measurable overhead for everybody. There might
be some small argument for putting these in under an extra #ifdef, but
they wouldn't get into any regular production build.

regards, tom lane