Feature #2837: Compile-time constant for HEAP_GROWTH_FACTOR (patch attached)

• Status: Closed
• Assignee: authorNari (Narihiro Nakamura)
• Target version: 2.6

[adgar (Michael Edgar)]

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The GC currently increases the size at which newly-created heaps by a factor of 1.8 for each heap. Some find it appropriate to modify this value (REE uses a value of 1 instead of 1.8, for example). In the trunk version of this code, that value is hard-coded in as a constant at 1.8 in gc.c:980.

I've included a patch to expose this as a compile-time constant (HEAP_GROW_FACTOR), and also included getters and setters in the style of the patch I submitted in Issue 1047: http://redmine.ruby-lang.org/issues/show/1047 .
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[nobu (Nobuyoshi Nakada)]

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Hi,

At Fri, 5 Mar 2010 05:20:36 +0900,
Michael Edgar wrote in [ruby-core:28487]:

I've included a patch to expose this as a compile-time
constant (HEAP_GROW_FACTOR), and also included getters and
setters in the style of the patch I submitted in Issue 1047:
http://redmine.ruby-lang.org/issues/show/1047 .

At least, they must be members of rb_objspace_t, and the
argument ranges should be checked.

--
Nobu Nakada

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[adgar (Michael Edgar)]

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At least, they must be members of rb_objspace_t, and the
argument ranges should be checked.

I considered this, though they are compile-time constants that are being replaced. Pre-patch, they aren't currently in the rb_objspace_t. The malloc_limit accessor affects the currently rb_objspace_t as appropriate, but the HEAP_MIN_SLOTS accessors don't since that value doesn't directly affect existing structures. I can certainly put a heap_min_slots member into rb_objspace_t.

Also, which argument ranges are considered valid? Perhaps a malloc_limit of at least 10K? I don't know how small of a footprint Ruby could fit into that people would like. While most people increase these values beyond their initial defaults, I wouldn't want to set the limit too low.

Thanks!
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[znz (Kazuhiro NISHIYAMA)]

• Target version set to 2.0.0

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[nahi (Hiroshi Nakamura)]

• Description updated (diff)
• Assignee set to authorNari (Narihiro Nakamura)

[shyouhei (Shyouhei Urabe)]

• Status changed from Open to Assigned

[authorNari (Narihiro Nakamura)]

• Target version changed from 2.0.0 to 2.6

[nobu (Nobuyoshi Nakada)]

This patch contains not only the subject but also the accessors.
It isn't acceptable and you should separate them, I think.

[authorNari (Narihiro Nakamura)]

• Status changed from Assigned to Closed

I commited r39746.
We can change HEAP_GROWTH_FACTOR via an enviroment variable now.
So I close this ticket.

Thanks.