From: Jeff King <peff@peff.net>
Date: Sun, 20 Jul 2025 00:03:59 GMT
Subject: Re: [PATCH 1/3] commit: convert pop_most_recent_commit() to prio_queue
Message-ID: <20250720000359.GA743449@coredump.intra.peff.net>
In-Reply-To: <37f34e15-f44f-4b8a-b684-bda27a977775@web.de>

On Sat, Jul 19, 2025 at 01:15:28PM +0200, René Scharfe wrote:

> > Hmm, I would have thought prio_queue had less memory overhead. You're
> > spending one pointer per entry in a packed array, versus list nodes. But
> > it's true that it doesn't shrink as items are removed (though that is
> > something we _could_ implement).
> 
> If we just count the net data then a commit_list item has two pointers
> and a prio_queue_entry has a pointer and an ID for stability.  That's a
> tie.  ALLOC_GROW overallocates by ca. 50%, so that's 25% more on
> average for the prio_queue.  No idea what overhead malloc() needs per
> allocation, but I guess it's enough to tilt the scale back against
> commit_lists.

Oh right, I totally forgot about the extra counter.

-Peff