ptmalloc2?

Christopher Faylor cgf@alum.bu.edu
Fri May 14 03:55:00 GMT 2004


On Thu, May 13, 2004 at 04:13:00PM -0500, Brian Ford wrote:
>On Thu, 13 May 2004, Christopher Faylor wrote:
>>Why does using ptmalloc buy you anything over the current scheme?
>
>Since I'm not very far into the port yet, I'm taking Doug Lea and
>Wolfram Gloger's word for it, but ptmalloc was specifically designed
>with SMP/multi-threading in mind to reduce contention.  That is the
>assumed advantage.  I also assumed that if it was good enough for
>glibc/Linux, then it might be good enough/better for us too.
>
>>You're asking if it's a good idea to use something without stating any
>>benefits.
>
>I'm asking for obvious up front objections/encouragment and pointers to
>gotchas, especially license wise since I'm not very familiar with that
>issue (contributing ports of code you didn't write with compatable
>licenses).
>
>I assumed people on this list might be familiar with different malloc
>implimentations, and I thought I expressed my intent to attack a
>certain specific (at least percieved) problem; thread contention.
>
>I'm confused about what was unclear.

You sent email saying "We're seeing thread contention so I thought I'd
contribute a port of ptmalloc2".

The reader is left to do some inferring.  One could infer that you think
that ptmalloc2 is better at eliminating the thread contention that you
think you have.  One could surmise that you think that any decisions that
glibc makes are ok for cygwin and so need no further technical review.
In this message you mention a new name: "Wolfram Gloger", and we are
left to conclude that he must be some kind of malloc genius whom we should
hang our heads in shame for not knowing.

If you have a need and want to make a major change to a fundamental part
of cygwin, don't expect that everyone will drop everything and jump on
over to glibc sources (or google) to look around to see what you're
talking about.  Make a technical argument for what you want and don't
waste our time with assumptions about your perception of our familiarity
with malloc implementations.  Don't expect us to trust either you, glibc
developers, or Wolfram Gloger to come to correct conclusions about what
is required for cygwin.

In short, don't waste my time with vague assertions of a problem
followed by vague suggestions of a fix, and then jump to assumptions of
the problems in integration before you've even proven that there is a
problem or that the proposed fix solves the problem.

Is this blunt enough for you?

cgf



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