From: Derrick Stolee <derrickstolee@github.com>
To: Taylor Blau <me@ttaylorr.com>
Cc: Junio C Hamano <gitster@pobox.com>,
git@vger.kernel.org, Jeff King <peff@peff.net>
Subject: Re: [PATCH 0/3] pack-bitmap: boundary-based bitmap traversal
Date: Tue, 25 Apr 2023 15:52:29 -0400 [thread overview]
Message-ID: <5943de3d-3dad-c600-c6d6-3c10c2851071@github.com> (raw)
In-Reply-To: <ZEgikbdP8M2sDMlM@nand.local>
On 4/25/2023 2:57 PM, Taylor Blau wrote:
> On Tue, Apr 25, 2023 at 02:30:01PM -0400, Derrick Stolee wrote:
>> It would be interesting if we used the initial commit walk to the
>> boundary as a predictor of whether bitmaps would be good, or if
>> we should use the tree-parsing walk instead.
>
> I think that this is tough, too. When making a prediction, it would be
> good if we could avoid walking down to the nearest bitmap, since by that
> point, you might as well have used bitmaps (if you found one before
> reaching the root(s) of history).
This isn't quite as cut-and-dry, because walking commits is much
faster than walking trees. I agree that we shouldn't walk too far
to avoid wasting time, but somehow we'd want to think about the
distance between the commits we want to cover and the bitmap(s)
we found in their history.
>> But perhaps this series gets the bitmap walk "close enough" in
>> the typical case that it's better to use bitmaps in the chance that
>> we have accidentally hit a case where we'd normally need to walk a
>> lot of trees.
>
> Yeah, that is definitely part of this series's goal. Another framing is,
> for configurations that are using bitmaps everywhere, this should reduce
> the number of cases where using bitmaps is *significantly* slower than
> not.
It's a good opportunity to re-think if we should be using bitmaps in
these contexts at all, or if there is a simpler thing to do by
disabling them when 'haves' exist. I don't think that's the right
thing to do in all cases, but the experiments you've demonstrated here
seem to point in that direction.
Thanks,
-Stolee
next prev parent reply other threads:[~2023-04-25 19:52 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-25 0:00 [PATCH 0/3] pack-bitmap: boundary-based bitmap traversal Taylor Blau
2023-04-25 0:00 ` [PATCH 1/3] revision: support tracking uninteresting commits Taylor Blau
2023-04-25 18:15 ` Derrick Stolee
2023-05-03 21:48 ` Taylor Blau
2023-05-04 13:46 ` Derrick Stolee
2023-05-03 22:08 ` Taylor Blau
2023-05-04 13:59 ` Derrick Stolee
2023-05-05 17:30 ` Taylor Blau
2023-04-25 18:22 ` Junio C Hamano
2023-04-25 18:48 ` Taylor Blau
2023-04-25 0:00 ` [PATCH 2/3] pack-bitmap.c: extract `fill_in_bitmap()` Taylor Blau
2023-04-25 18:32 ` Junio C Hamano
2023-04-25 18:51 ` [PATCH 2/3] pack-bitmap.c: extract `fill_in_bitmap()`t Taylor Blau
2023-04-25 0:00 ` [PATCH 3/3] pack-bitmap.c: use commit boundary during bitmap traversal Taylor Blau
2023-04-25 18:52 ` Junio C Hamano
2023-05-02 21:31 ` Felipe Contreras
2023-05-03 21:42 ` Taylor Blau
2023-05-03 21:58 ` Junio C Hamano
2023-04-25 18:53 ` Derrick Stolee
2023-04-25 18:02 ` [PATCH 0/3] pack-bitmap: boundary-based " Junio C Hamano
2023-04-25 18:30 ` Derrick Stolee
2023-04-25 18:57 ` Taylor Blau
2023-04-25 19:52 ` Derrick Stolee [this message]
2023-05-03 21:43 ` Taylor Blau
2023-04-25 18:06 ` Derrick Stolee
2023-04-25 19:01 ` Taylor Blau
2023-04-25 20:27 ` Derrick Stolee
2023-05-01 22:08 ` Junio C Hamano
2023-05-02 23:52 ` Taylor Blau
2023-05-05 17:27 ` [PATCH v2 0/2] " Taylor Blau
2023-05-05 17:27 ` [PATCH v2 1/2] pack-bitmap.c: extract `fill_in_bitmap()` Taylor Blau
2023-05-05 17:27 ` [PATCH v2 2/2] pack-bitmap.c: use commit boundary during bitmap traversal Taylor Blau
2023-05-05 18:13 ` Derrick Stolee
2023-05-05 18:43 ` Taylor Blau
2023-05-05 17:33 ` [PATCH v2 0/2] pack-bitmap: boundary-based " Junio C Hamano
2023-05-05 17:59 ` Derrick Stolee
2023-05-05 18:46 ` [PATCH v2 0/2] pack-bitmap: boundary-based bitmap traversalt Taylor Blau
2023-05-05 20:45 ` Derrick Stolee
2023-05-08 17:38 ` [PATCH v3 0/3] pack-bitmap: boundary-based bitmap traversal Taylor Blau
2023-05-08 17:38 ` [PATCH v3 1/3] object: add object_array initializer helper function Taylor Blau
2023-05-08 17:38 ` [PATCH v3 2/3] pack-bitmap.c: extract `fill_in_bitmap()` Taylor Blau
2023-05-08 17:38 ` [PATCH v3 3/3] pack-bitmap.c: use commit boundary during bitmap traversal Taylor Blau
2023-05-08 20:53 ` Derrick Stolee
2023-05-08 22:12 ` Taylor Blau
2023-05-10 22:55 ` [PATCH v3 0/3] pack-bitmap: boundary-based " Junio C Hamano
2023-05-10 23:10 ` Taylor Blau
2023-05-11 15:23 ` Derrick Stolee
2023-06-08 16:25 ` [PATCH v4 " Taylor Blau
2023-06-08 16:25 ` [PATCH v4 1/3] object: add object_array initializer helper function Taylor Blau
2023-06-08 16:25 ` [PATCH v4 2/3] pack-bitmap.c: extract `fill_in_bitmap()` Taylor Blau
2023-06-08 16:25 ` [PATCH v4 3/3] pack-bitmap.c: use commit boundary during bitmap traversal Taylor Blau
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