This perf script creates a midx by running "git multi-pack-index write"
with the "--stdin-packs" option. We feed that stdin by running "find" on
.git/objects/pack, using sed to strip off everything but the basename.
But that sed invocation also does something peculiar: it adds a "+" to
the start of each pack name. This causes the multi-pack-index command to
barf. The modified name does not match any pack it knows about, so it
ends up with an empty list of packs to put in the midx. And thus nothing
matches the --preferred-pack option we pass, which causes it die().
The fix is to remove the extra "+" (which also lets us simplify the sed
invocation a bit, as it is now just stripping the leading directories).
But that leaves the mystery of why it was ever there in the first place.
The answer is that an earlier iteration of the patch series had a
concept of "disjoint" packs in the midx. And one of its patches here:
https://lore.kernel.org/git/c52d7e7b27a9add4f58b8334db4fe4498af1c90f.1701198172.git.me@ttaylorr.com/
taught read_packs_from_stdin() to treat a leading "+" as marking a
disjoint pack. But in the second version of the series, which was
ultimately merged, that disjoint concept went away, and the code to
parse "+" did likewise. The regular regression tests were adjusted to
match, but this case in t/perf was forgotten.
Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The perf test suite prefers to use test_file_size over 'wc -c' when
inside of a test_size block. One advantage is that accidentally writign
"wc -c file" (instead of "wc -c <file") does not inadvertently break the
tests (since the former will include the filename in the output of wc).
Both of the two uses of test_size use "wc -c", but let's convert those
to the more conventional test_file_size helper instead.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To ensure that we don't regress either the size or runtime performance
of multi-pack reuse, add a performance test to measure both of these.
The test partitions the objects in GIT_TEST_PERF_LARGE_REPO into 1, 10,
and 100 packs, and then tries to perform a "clone" at each stage with
both single- and multi-pack reuse enabled.
Note that the `repack_into_n_chunks()` function in this new test script
differs from the existing `repack_into_n()`. The former partitions the
repository into N equal-sized chunks, while the latter produces N packs
of five commits each (plus their objects), and then another pack with
the remainder.
On git.git, I can produce the following results on my machine:
Test this tree
--------------------------------------------------------------------------------
5332.3: clone for 1-pack scenario (single-pack reuse) 1.57(2.99+0.15)
5332.4: clone size for 1-pack scenario (single-pack reuse) 231.8M
5332.5: clone for 1-pack scenario (multi-pack reuse) 1.79(2.96+0.21)
5332.6: clone size for 1-pack scenario (multi-pack reuse) 231.7M
5332.9: clone for 10-pack scenario (single-pack reuse) 3.89(16.75+0.35)
5332.10: clone size for 10-pack scenario (single-pack reuse) 209.9M
5332.11: clone for 10-pack scenario (multi-pack reuse) 1.56(2.99+0.17)
5332.12: clone size for 10-pack scenario (multi-pack reuse) 224.4M
5332.15: clone for 100-pack scenario (single-pack reuse) 8.24(54.31+0.59)
5332.16: clone size for 100-pack scenario (single-pack reuse) 278.3M
5332.17: clone for 100-pack scenario (multi-pack reuse) 2.13(2.44+0.33)
5332.18: clone size for 100-pack scenario (multi-pack reuse) 357.9M
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano