mercurial: Changelog

stream-clone: avoid opening a revlog in case we do not need it Opening an revlog has a cost, especially if it is inline as we have to scan the file and construct an index. To prevent the associated slowdown, we just do a minimal scan to check that an inline file is still inline, and simply stream the file without creating a revlog when we can. This provides a big boost compared to the previous changeset, even if the full generation is still penalized by the initial gathering of information. All benchmarks are run on linux with Python 3.10.7. # benchmark.name = hg.exchange.stream.generate # benchmark.variants.version = v2 ### Compared to the previous changesets We get a large win all across the board! # mercurial-2018-08-01-zstd-sparse-revlog before: 0.250694 seconds after: 0.105986 seconds (-57.72%) # pypy-2018-08-01-zstd-sparse-revlog before: 3.885657 seconds after: 1.709748 seconds (-56.00%) # netbeans-2018-08-01-zstd-sparse-revlog before: 16.679371 seconds after: 7.687469 seconds (-53.91%) # mozilla-central-2018-08-01-zstd-sparse-revlog before: 38.575482 seconds after: 17.520316 seconds (-54.58%) # mozilla-try-2019-02-18-zstd-sparse-revlog before: 81.160994 seconds after: 37.073753 seconds (-54.32%) ### Compared to 6.4.3 We are still significantly slower than 6.4.3, the extra time is usually twice slower than the extra time we observe on the locked section, which is a quite interesting information. Except for mercurial-central that is much faster. That discrepancy is not really explained yet. # mercurial-2018-08-01-zstd-sparse-revlog 6.4.3: 0.072560 seconds after: 0.105986 seconds (+46.07%) (- 0.03 seconds) # pypy-2018-08-01-zstd-sparse-revlog 6.4.3: 1.211193 seconds after: 1.709748 seconds (+41.16%) (-0.45 seconds) # netbeans-2018-08-01-zstd-sparse-revlog 6.4.3: 4.932843 seconds after: 7.687469 seconds (+55.84%) (-2.75 seconds) # mozilla-central-2018-08-01-zstd-sparse-revlog 6.4.3: 34.012226 seconds after: 17.520316 seconds (-48.49%) (-16.49 seconds) # mozilla-try-2019-02-18-zstd-sparse-revlog 6.4.3: 23.850555 seconds after: 37.073753 seconds (+55.44%) (+13.22 seconds)

store: stop relying on a `revlog_type` property We want to know if a file is related to a revlog, but the rest is dealt with differently already, so we simplify things further. as a bonus, this cleanup This provides a small but noticeable speedup. The number below use `hg perf::stream-locked-section` to measure the time spend in the locked section of the streaming clone. Number are run on various repository and compare different steps.: 1) the effect of this patchs, 2) the effect of the cleanup series, 2) current state compared to because large refactoring. All benchmarks are run on linux with Python 3.10.7. ### Effect of this patch # mercurial-2018-08-01-zstd-sparse-revlog # benchmark.name = perf-stream-locked-section before: 0.030246 seconds after: 0.029274 seconds (-3.21%) # pypy-2018-08-01-zstd-sparse-revlog before: 0.545012 seconds after: 0.520872 seconds (-4.43%) # netbeans-2018-08-01-zstd-sparse-revlog before: 2.719939 seconds after: 2.626791 seconds (-3.42%) # mozilla-central-2018-08-01-zstd-sparse-revlog before: 6.304179 seconds after: 6.096700 seconds (-3.29%) # mozilla-try-2019-02-18-zstd-sparse-revlog before: 14.142687 seconds after: 13.640779 seconds (-3.55%) ### Effect of this series A small but sizeable speedup # mercurial-2018-08-01-zstd-sparse-revlog before: 0.031122 seconds after: 0.029274 seconds (-5.94%) # pypy-2018-08-01-zstd-sparse-revlog before: 0.589970 seconds after: 0.520872 seconds (-11.71%) # netbeans-2018-08-01-zstd-sparse-revlog before: 2.980300 seconds after: 2.626791 seconds (-11.86%) # mozilla-central-2018-08-01-zstd-sparse-revlog before: 6.863204 seconds after: 6.096700 seconds (-11.17%) # mozilla-try-2019-02-18-zstd-sparse-revlog before: 14.921393 seconds after: 13.640779 seconds (-8.58%) ### Current state compared to the pre-refactoring state The refactoring introduced multiple string manipulation and dictionary creation that seems to induce a signifiant slowdown Slowdown # mercurial-2018-08-01-zstd-sparse-revlog 6.4.3: 0.019459 seconds after: 0.029274 seconds (+50.44%) ## pypy-2018-08-01-zstd-sparse-revlog 6.4.3: 0.290715 seconds after: 0.520872 seconds (+79.17%) # netbeans-2018-08-01-zstd-sparse-revlog 6.4.3: 1.403447 seconds after: 2.626791 seconds (+87.17%) # mozilla-central-2018-08-01-zstd-sparse-revlog 6.4.3: 3.163549 seconds after: 6.096700 seconds (+92.72%) # mozilla-try-2019-02-18-zstd-sparse-revlog 6.4.3: 6.702184 seconds after: 13.640779 seconds (+103.53%)

store: directly pass the filesize in the `details` of revlog The dictionary only contains 1 (or 0) entries, we can directly store that information (or None). Moving to a simpler argument passing result in a noticable speedup (because Python) The number below use `hg perf::stream-locked-section` to measure the time spend in the locked section of the streaming clone. Number are run on various repository. ### mercurial-2018-08-01-zstd-sparse-revlog before: 0.031247 seconds after: 0.030246 seconds (-3.20%) ### mozilla-central-2018-08-01-zstd-sparse-revlog before: 6.718968 seconds after: 6.304179 seconds (-6.17%) ### mozilla-try-2019-02-18-zstd-sparse-revlog before: 14.631343 seconds after: 14.142687 seconds (-3.34%) ### netbeans-2018-08-01-zstd-sparse-revlog before: 2.895584 seconds after: 2.719939 seconds (-6.07%) ### pypy-2018-08-01-zstd-sparse-revlog before: 0.561843 seconds after: 0.543034 seconds (-3.35%)

store: explicitly pass file_size when creating StoreFile A small cleanup before large cleanup in the next patch.

store: have the revlog determine which files are volatile itself This is a first step toward simplifying the walk step.

test-dirstate-version-fallback: future-proof the test for a different default Dirstate-v2 will become the default at some point, which would cause this test to fail. Let's save someone else the headache later.

clonebundles: add support for inline (streaming) clonebundles The idea behind inline clonebundles is to send them through the ssh or https connection to the Mercurial server. We've been using this specifically for streaming clonebundles, although it works for 'regular' clonebundles as well (but is less relevant, since pullbundles exist). We've had this enabled for around 9 months for a part of our users. A few benefits are: - no need to secure an external system, since everything goes through the same Mercurial server - easier scaling (in our case: no risk of inconsistencies between multiple mercurial-server mirrors and nginx clonebundles hosts) Remaining topics/questions right now: - The inline clonebundles don't work for https yet. This is because httppeer doesn't seem to support sending client capabilities. I didn't focus on that as my main goal was to get this working for ssh.