[m-dev.] enabling stseg component by default

[Paul Bone]

On Wed, May 22, 2013 at 02:34:22PM +1000, Julien Fischer wrote:
>
>
> On Wed, 22 May 2013, Paul Bone wrote:
>
>> On Tue, May 21, 2013 at 05:14:22PM +1000, Julien Fischer wrote:
>>>
>>> Hi all,
>>>
>>> I propose that we enable the stseg (stack segments) grade component
>>> by default for all low-level C grades in the post 13.05 versions
>>> of the compiler.
>>>
>>> Any objections?
>>
>> I don't mind.  Although the memory zones code probably needs further tuning,
>
> In which respect?

There are three things I"m aware of:

    1) You requested a way to get stats about memory zone usage, I never
       implemented this.
    2) The caching and freeing of zones (how many do we cache, what policy
       is used to prevent the cache from growing too large) has never been
       benchmarked/tuned.
    3) I planned, but never implemented, per-engine caching of stack zones
       in parallel grades (in addition to a global cache).  My current
       thinking is that an engine should hang onto a small number of zones,
       1 or perhaps 2 so that if a process keeps crossing a zone threshold
       it doesn't need to bother the global cache often.  The local cache's
       data structure should also be very simple to make this operation as
       quick as possible.

-- 
Paul Bone
http://www.bone.id.au