Nicholas Clark <[EMAIL PROTECTED]> writes:
> On Thu, Oct 03, 2002 at 02:35:14PM -0400, Benjamin Goldberg wrote:
>
> > If "what it does" is merely return the value of the C sbrk() function,
> > then IMHO, sbrk() is a perfectly good name.
> >
> > However, as to other possible names -- how about ProcessSize() ? I'm
> > not sure if this is really a valid description of what sbrk() returns,
> > though.
>
> I'm not certain it's as accurate as we might like to think. I am under the
> impression (quite possibly wrong, as I don't have the source code handy) that
>
> 1: Doug Lea's malloc will do anonymous mmap() to satisfy really big requests
> 2: glib malloc is a variant derived from Doug Lea's code
^^^^
glibc (glib has its own g_malloc function)
You're right. With glibc-2.1.2, it seems that malloc falls back to
mmap for requests larger than 128K. Which is quite cool and maybe
should be implemented in perl's mymalloc.
>
> Hence is it plausible that systems exist where the malloc that perl calls
> may normally get memory from the system with sbrk(), but occasionally use
> somewhere other than the system heap. So perl code might cause more memory to
> be used, but if we report back sbrk() as process size we're actually claiming
> a bit more for our "fact" than we can actually be sure of.
>
> If we call it sbrk() we can divorce ourselves from actually claiming that it
> is the one true source of memory :-)
>
> Not that this is helpful - I guess we want a direct sbrk() interface if sbrk()
> is on the system, and a process size interface that makes the best estimate it
> can.
>
> But I'm not writing this thing, and so far I guess I've not wanted it *that*
> much. [mm. maybe I have. number 3 on my hitlist of "what slows perl" is RAM.
> So seeing if a data structure change reduces RAM is interesting to me, the
> encode compiler, and everyone building perl from source]
>
> Nicholas Clark
Regards,
Slaven
--
Slaven Rezic - [EMAIL PROTECTED]
babybike - routeplanner for cyclists in Berlin
handheld (e.g. Compaq iPAQ with Linux) version of bbbike
http://bbbike.sourceforge.net
