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From: Goswin von Brederlow <goswin-v-b@web.de>
To: Warren Harris <warrensomebody@gmail.com>
Cc: OCaml <caml-list@inria.fr>
Subject: Re: [Caml-list] gc overhead
References: <37150F07-8902-464A-9A0E-44A0C424C87B@gmail.com>
Date: Wed, 03 Mar 2010 12:11:06 +0100
In-Reply-To: <37150F07-8902-464A-9A0E-44A0C424C87B@gmail.com> (Warren Harris's
	message of "Sun, 28 Feb 2010 16:16:03 -0800")
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X-Spam: no; 0.00; implements:01 compaction:01 warren:98 warren:98 increments:98 mfg:98 garbage:01 caml-list:01 short:01 writes:01 cached:02 objects:02 objects:02 gprof:03 overhead:04 

Warren Harris <warrensomebody@gmail.com> writes:

> I would like to determine what percentage of my application's cpu time
> is spent in the garbage collector (for tuning purposes, but also just
> to monitor the overhead). Is there any way to obtain this information
> short of using gprof? Additional information provided by Gc.stat would
> be ideal, or perhaps a Gc.alarm that was called at the beginning of
> the gc cycle, but neither of these seem to exist.
>
> Warren

In my code I have a cache structure that implements a last-recently-used
ordering of cached objects. As objects are used the list grows an every
now and then I have to shrink it. It would be real nice if I could
shrink it exactly before evrey GC major cycle or compaction.

I also saw that Gc.alarm is called AFTER each GC cycle. But maybe that
doesn't matter as after a cycle is before a cycle. With the major cycle
being done in increments the next cycle probably starts right after the
last one finished compared to the time the cycle takes overall.

MfG
        Goswin