From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org
Subject: Re: [PATCH 6/6] pack-objects: reuse on-disk deltas for thin "have" objects
Date: Mon, 20 Aug 2018 14:03:53 -0700 [thread overview]
Message-ID: <xmqqa7pgbvie.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20180817210604.GF20088@sigill.intra.peff.net> (Jeff King's message of "Fri, 17 Aug 2018 17:06:04 -0400")
Jeff King <peff@peff.net> writes:
> And that's exactly what this patch does: when we're
> considering whether to reuse an on-disk delta, if bitmaps
> tell us the other side has the object (and we're making a
> thin-pack), then we reuse it.
That's really the natural extension and logical consequence of the
"reuse existing deltas" mechanism from Feb 2006 ;-)
> So taking all of those options into account, what I ended up
> with is a separate list of "external bases" that are not
> part of the main packing list. Each delta entry that points
> to an external base has a single-bit flag to do so; we have a
> little breathing room in the bitfield section of
> object_entry.
>
> This lets us limit the change primarily to the oe_delta()
> and oe_set_delta_ext() functions. And as a bonus, most of
> the rest of the code does not consider these dummy entries
> at all, saving both runtime CPU and code complexity.
Tricky ;-)
I wonder if we can move the preferred base objects that we are not
going to send also off of the "main packing list" to this new
mechanism?
> +static struct bitmap_index *bitmap_git;
> ...
> +static int thin = 0;
Please trust what BSS will do to your static vars.
next prev parent reply other threads:[~2018-08-20 21:04 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-17 20:54 [PATCH 0/6] reuse on-disk deltas for fetches with bitmaps Jeff King
2018-08-17 20:55 ` [PATCH 1/6] t/perf: factor boilerplate out of test_perf Jeff King
2018-08-17 20:55 ` [PATCH 2/6] t/perf: factor out percent calculations Jeff King
2018-08-17 20:56 ` [PATCH 3/6] t/perf: add infrastructure for measuring sizes Jeff King
2018-08-17 20:57 ` [PATCH 4/6] t/perf: add perf tests for fetches from a bitmapped server Jeff King
2018-08-17 20:59 ` [PATCH 5/6] pack-bitmap: save "have" bitmap from walk Jeff King
2018-08-17 22:39 ` Stefan Beller
2018-08-17 22:45 ` Jeff King
2018-08-17 21:06 ` [PATCH 6/6] pack-objects: reuse on-disk deltas for thin "have" objects Jeff King
2018-08-17 22:57 ` Stefan Beller
2018-08-17 23:32 ` Jeff King
2018-08-20 21:03 ` Junio C Hamano [this message]
2018-08-20 21:42 ` Jeff King
2018-08-21 19:06 ` [PATCH v2 0/6] reuse on-disk deltas for fetches with bitmaps Jeff King
2018-08-21 19:08 ` Jeff King
2018-08-21 19:34 ` Junio C Hamano
2018-08-21 19:51 ` Jeff King
2018-08-21 18:41 [PATCH] test-tool.h: include git-compat-util.h Jeff King
2018-08-21 19:07 ` [PATCH 6/6] pack-objects: reuse on-disk deltas for thin "have" objects Jeff King
2018-08-21 19:43 ` Junio C Hamano
2018-08-21 19:50 ` Junio C Hamano
2018-08-21 20:07 ` Jeff King
2018-08-21 20:14 ` Jeff King
2018-08-21 20:52 ` Junio C Hamano
2018-08-21 21:30 ` Jeff King
2018-08-21 20:57 ` Junio C Hamano
2018-08-21 21:32 ` Jeff King
2018-08-21 20:00 ` Jeff King
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