On Feb 22, 2:34 pm, mabshoff <mabsh...@googlemail.com> wrote:
> On Feb 22, 2:19 pm, "Georg S. Weber" <georgswe...@googlemail.com>
> wrote:
>
> > Hi sage-devel,
>
> Hi,
>
>
>
> > currently Sage uses, if possible, the system's malloc.
> > This has a big advantage --- that strategy certainly is the one
> > supporting portability of Sage best.
>
> > I don't know if there is a timeline already for the use of customized
> > "Sage malloc" versions for some (or all) systems Sage runs on.
>
> > But one obstacle in the past has been that Singular/omalloc had
> > hardcoded the use of its own copy (slightly adapted source code) of
> > Doug Lea's dlmalloc v2.6.5 from 1998 (see
> > e.g.http://en.wikipedia.org/wiki/Doug_Lea
> > --- there is also a link to a code repository).
>
> > The most recent dlmalloc has the version number v2.8.3, and there are
> > interesting remarks in its history/comments since v2.6.5. Like "don't
> > use sbrk on Macs"; and "modern Linux kernels may still be able to
> > serve memory via mmap, even if sbrk fails to do so, so now do use mmap
> > as a backup strategy".
>
> > But up to now, if in Singular/omalloc one wanted to switch away from
> > the default dlmalloc v2.6.5, one ran into a "double free" problem (at
> > least under Mac OS X, and Cygwin). This even happens, if one plugs
> > back in the "default" dlmalloc code! To my knowledge, Michael Abshoff
> > was the first one to report this here in sage-devel, but I couldn't
> > find an appropriate trac ticket. So I created #5344 for this.
>
> > And there's now a patch waiting for review :-).
>
> "Needs work" - it breaks 25 doctests on OSX by introducing segfaults.
> See the comments I made on the ticket.
Oooh, I think I was completely wrong :(, so I am changing my mind to
neutral with a likely output of positive review.
Georg: Please write shorter ticket descriptions in the future for the
less patient among us. That makes it less likely that I will look like
an idiot in public :)
Cheers,
Michael
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