#715: Parents probably not reclaimed due to too much caching
--------------------------------------------------+-------------------------
Reporter: robertwb | Owner: somebody
Type: defect | Status:
needs_review
Priority: major | Milestone: sage-5.0
Component: coercion | Resolution:
Keywords: weak cache coercion Cernay2012 | Work issues:
Report Upstream: N/A | Reviewers: Jean-Pierre
Flori
Authors: Simon King | Merged in:
Dependencies: #9138, #11900, #11599, #11521 | Stopgaps:
--------------------------------------------------+-------------------------
Old description:
> Here is a small example illustrating the issue.
>
> The memory footprint of the following piece of code grows indefinitely.
>
> {{{
> sage: K = GF(1<<55,'t')
> sage: a = K.random_element()
> sage: while 1:
> ....: E = EllipticCurve(j=a); P = E.random_point(); 2*P; del E, P;
>
> }}}
> E and P get deleted, but when 2*P is computed, the action of integers on
> A, the abelian group of rational points of the ellitpic curve, gets
> cached in the corecion model.
>
> A key-value pair is left in coercion_model._action_maps dict:
>
> (ZZ,A,*) : IntegerMulAction
>
> Moreover there is at least also references to A in the IntegerMulAction
> and one in ZZ._action_hash.
>
> So weak refs should be used in all these places if it does not slow
> things too much.
>
> '''To be merged with #11521'''. Apply:
>
> * [attachment:trac_715-one_triple_dict-take2.patch]
> * [attachment:trac_715-reviewer-take2.patch]
> * [attachment:trac_715-rebase_11599-take2.patch]
> * [attachment:trac_715-size_t-take2.patch]
>
> and '''then''' the tickets from #11521.
New description:
Here is a small example illustrating the issue.
The memory footprint of the following piece of code grows indefinitely.
{{{
sage: K = GF(1<<55,'t')
sage: a = K.random_element()
sage: while 1:
....: E = EllipticCurve(j=a); P = E.random_point(); 2*P; del E, P;
}}}
E and P get deleted, but when 2*P is computed, the action of integers on
A, the abelian group of rational points of the ellitpic curve, gets cached
in the corecion model.
A key-value pair is left in coercion_model._action_maps dict:
(ZZ,A,*) : IntegerMulAction
Moreover there is at least also references to A in the IntegerMulAction
and one in ZZ._action_hash.
So weak refs should be used in all these places if it does not slow things
too much.
'''To be merged with #11521'''. Apply:
* [attachment:trac_715_combined.patch]
and '''then''' the tickets from #11521.
--
Comment (by SimonKing):
I have just attached a combined patch, created by simply folding all
patches that were previously to be applied.
With ''only'' that patch, I obtain a single doctest error:
{{{
sage -t -force_lib "devel/sage/sage/structure/coerce_dict.pyx"
**********************************************************************
File
"/mnt/local/king/SAGE/stable/sage-5.0.beta13/devel/sage/sage/structure/coerce_dict.pyx",
line 210:
sage: len(LE) # indirect doctest
Expected:
1
Got:
50
}}}
However, this is to be merged together with #11521, and with both tickets
together the error vanishes (at least on 64 bit). So, from my point of
view, it is a positive review, but we should wait for Jean-Pierre's
results on 32 bit.
For the patchbot:
Apply trac_715_combined.patch
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/715#comment:187>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
