On tis, 2010-11-30 at 15:49 -0500, Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
> > On mån, 2010-11-29 at 13:10 -0500, Tom Lane wrote:
> >> Rolling in calloc in place of
> >> malloc/memset made no particular difference either, which says that
> >> Fedora 13's glibc does not have any optimization for that case as I'd
> >> hoped.
>
> > glibc's calloc is either mmap of /dev/zero or malloc followed by memset.
>
> Hmm. I would have expected to see a difference then. Do you know what
> conditions are needed to cause the mmap to be used?
Check out the mallopt(3) man page. It contains a few tunable malloc
options that may be useful for your investigation.