From: Junio C Hamano <gitster@pobox•com>
To: Jeff King <peff@peff•net>
Cc: "René Scharfe" <l.s.r@web•de>, "Git List" <git@vger•kernel.org>
Subject: Re: [PATCH 1/3] commit: convert pop_most_recent_commit() to prio_queue
Date: Sat, 19 Jul 2025 18:22:51 -0700 [thread overview]
Message-ID: <xmqqseirzmdw.fsf@gitster.g> (raw)
In-Reply-To: <20250720000359.GA743449@coredump.intra.peff.net> (Jeff King's message of "Sat, 19 Jul 2025 20:03:59 -0400")
Jeff King <peff@peff•net> writes:
> 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.
Don't feel bad. I forgot about it, too, when I gave my "is it
stable?" comment to René's patch. ;-)
next prev parent reply other threads:[~2025-07-20 1:22 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-15 14:35 [PATCH 0/3] commit: convert pop_most_recent_commit() to prio_queue René Scharfe
2025-07-15 14:51 ` [PATCH 1/3] " René Scharfe
2025-07-15 19:23 ` Junio C Hamano
2025-07-15 20:47 ` Justin Tobler
2025-07-16 9:39 ` René Scharfe
2025-07-16 5:05 ` Jeff King
2025-07-16 9:39 ` René Scharfe
2025-07-17 8:22 ` René Scharfe
2025-07-19 6:55 ` Jeff King
2025-07-19 6:57 ` Jeff King
2025-07-19 11:15 ` René Scharfe
2025-07-20 0:03 ` Jeff King
2025-07-20 1:22 ` Junio C Hamano [this message]
2025-07-16 22:23 ` Junio C Hamano
2025-07-17 8:22 ` René Scharfe
2025-07-15 14:51 ` [PATCH 2/3] prio-queue: add prio_queue_replace() René Scharfe
2025-07-16 5:09 ` Jeff King
2025-07-16 9:38 ` René Scharfe
2025-07-17 9:20 ` René Scharfe
2025-07-19 7:02 ` Jeff King
2025-07-15 14:51 ` [PATCH 3/3] commit: use prio_queue_replace() in pop_most_recent_commit() René Scharfe
2025-07-15 20:43 ` Junio C Hamano
2025-07-16 9:38 ` René Scharfe
2025-07-16 0:07 ` [PATCH 0/3] commit: convert pop_most_recent_commit() to prio_queue Junio C Hamano
2025-07-16 5:15 ` Jeff King
2025-07-16 9:38 ` René Scharfe
2025-07-19 6:45 ` Jeff King
2025-07-16 14:49 ` Junio C Hamano
2025-07-18 9:09 ` [PATCH v2 " René Scharfe
2025-07-18 9:39 ` [PATCH v2 1/3] " René Scharfe
2025-07-21 14:02 ` Lidong Yan
2025-08-03 9:54 ` René Scharfe
2025-08-03 16:48 ` Junio C Hamano
2025-08-04 19:56 ` René Scharfe
2025-07-18 9:39 ` [PATCH v2 3/3] commit: use prio_queue_replace() in pop_most_recent_commit(),MIME-Version: 1.0 René Scharfe
2025-08-03 11:12 ` Johannes Schindelin
2025-08-03 11:33 ` René Scharfe
2025-07-18 9:39 ` [PATCH v2 2/3] prio-queue: add prio_queue_replace() René Scharfe
2025-07-19 7:04 ` [PATCH v2 0/3] commit: convert pop_most_recent_commit() to prio_queue Jeff King
2025-07-22 6:26 ` SZEDER Gábor
2025-07-22 14:27 ` Junio C Hamano
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