convert: stringify `shlex` class argument The documentation is handwavy, but typeshed says this should be `str`[1]. I'm not sure if this is the correct encoding (vs `fsencode` or "latin1" like the tokens returned by the proxy class). While we're here, we can add a few more type hints that would have caused pytype to flag the problem. [1] https://github.com/python/typeshed/blob/6a9b53e719a139c2d6b41cf265ed0990cf438192/stdlib/shlex.pyi#L51

typing: add trivial type hints to the convert extension's common modules This started as ensuring that the `encoding` and `orig_encoding` attributes has a type other than `Any`, so pytype can catch problems where it needs to be str for stdlib encoding and decoding. It turns out that adding the hint in `mercurial.encoding` is what was needed, but I picked a bunch of low hanging fruit while here. There's definitely more to do, and I see a problem where `shlex.shlex` is being fed bytes instead of str, but there are not enough type hints yet to make pytype notice.

convert: drop a duplicate implementation of `dateutil.makedate()` I noticed this because the signature generated by pytype recently changed to be less specific. When the method was introduced back in 337d728e644f, `util.makedate()` didn't take an optional timestamp arg. But now it does, and the methods are the same (except the `dateutil` version validates that the timestamp isn't a negative value). I left the old method in place in case anyone has custom convert code that monkey patches it.

revlog: use mmap by default is pre-population is available Using mmap has a great impact of memory usage on server, and a good impact on performance in multiple case. Now that we pre-populate memory mapping by default, there is case where it using mmap is slower. So we use it by default (if pre-population is available). Further work to reduce the performance impact of the pre-population will be done later. Some benchmark below (using the same setup as 522b4d729e89): As for 522b4d729e89 the impact on small repository like Mercurial or Pypy is tiny, ~1% best. However for large repositories we see some performance improvement without seeing the performance regression that we could have without pre-populate. ##### For netbeans ### data-env-vars.name = netbeans-2018-08-01-zstd-sparse-revlog ## benchmark.name = hg.command.log # bin-env-vars.hg.flavor = rust # benchmark.variants.limit-rev = 1 # benchmark.variants.patch = yes no-mmap: 0.171579 mmap: 0.166311 (-3.07%, -0.01) # bin-env-vars.hg.flavor = default no-mmap: 0.170716 mmap: 0.165218 (-3.22%, -0.01) # benchmark.variants.patch = no # benchmark.variants.rev = tip no-mmap: 0.140862 mmap: 0.137566 (-2.34%, -0.00) ## benchmark.name = hg.command.unbundle # bin-env-vars.hg.flavor = rust # benchmark.variants.issue6528 = disabled # benchmark.variants.reuse-external-delta-parent = yes # benchmark.variants.revs = any-1-extra-rev # benchmark.variants.source = unbundle no-mmap: 0.238038 mmap: 0.239912 no-populate: 0.cbd4c9 (+11.71%, +0.03) #### For Mozilla ### data-env-vars.name = mozilla-try-2019-02-18-ds2-pnm # benchmark.name = hg.command.log # bin-env-vars.hg.flavor = rust # bin-env-vars.hg.py-re2-module = default # benchmark.variants.limit-rev = 1 # benchmark.variants.patch = yes no-mmap: 0.258440 mmap: 0.237813 (-7.98%, -0.02) # benchmark.variants.limit-rev = 10 no-mmap: 1.235323 mmap: 1.213578 (-1.76%, -0.02) ## benchmark.name = hg.command.push # bin-env-vars.hg.flavor = rust # bin-env-vars.hg.py-re2-module = default # benchmark.variants.explicit-rev = none # benchmark.variants.issue6528 = disabled # benchmark.variants.protocol = ssh # benchmark.variants.reuse-external-delta-parent = yes # benchmark.variants.revs = any-1-extra-rev no-mmap: 4.790135 mmap: 4.668971 (-2.53%, -0.12) no-populate: 4.841141 (+1.06%, +0.05) ### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog ## benchmark.name = hg.command.log # bin-env-vars.hg.flavor = default # benchmark.variants.limit-rev = 1000 # benchmark.variants.rev = tip no-mmap: 0.206187 mmap: 0.197348 (-4.29%, -0.01) ## benchmark.name = hg.command.push # bin-env-vars.hg.flavor = default # benchmark.variants.explicit-rev = none # benchmark.variants.issue6528 = disabled # benchmark.variants.protocol = ssh # benchmark.variants.reuse-external-delta-parent = yes # benchmark.variants.revs = any-1-extra-rev no-mmap: 4.768259 mmap: 4.798632 no-populate: 4.953295 (+3.88%, +0.19) # benchmark.variants.revs = any-100-extra-rev no-mmap: 4.785946 mmap: 4.903618 no-populate: 5.014963 (+4.79%, +0.23) ## benchmark.name = hg.command.unbundle # bin-env-vars.hg.flavor = default # benchmark.variants.issue6528 = disabled # benchmark.variants.reuse-external-delta-parent = yes # benchmark.variants.revs = any-1-extra-rev # benchmark.variants.source = unbundle no-mmap: 1.400121 mmap: 1.423411 no-populate: 1.585365 (+13.23%, +0.19)

revlog: use an explicit config option to enable mmap usage for index We replace the `experimental.mmapindexthreshold` with two options: The `storage.revlog.mmap.index` is a boolean option to enable or disable the feature. The `storage.revlog.mmap.index:size-threshold` is a bytes option that control when we will be using mmap instead of plain reading.

mmap: populate the mapping by default Without pre-population, accessing all data through a mmap can result in many pagefault, reducing performance significantly. If the mmap is prepopulated, the performance can no longer get slower than a full read. (See benchmark number below) In some cases were very few data is read, prepopulating can be overkill and slower than populating on access (through page fault). So that behavior can be controlled when the caller can pre-determine the best behavior. (See benchmark number below) In addition, testing with populating in a secondary thread yield great result combining the best of each approach. This might be implemented in later changesets. In all cases, using mmap has a great effect on memory usage when many processes run in parallel on the same machine. ### Benchmarks # What did I run A couple of month back I ran a large benchmark campaign to assess the impact of various approach for using mmap with the revlog (and other files), it highlighted a few benchmarks that capture the impact of the changes well. So to validate this change I checked the following: - log command displaying various revisions (read the changelog index) - log command displaying the patch of listed revisions (read the changelog index, the manifest index and a few files indexes) - unbundling a few revisions (read and write changelog, manifest and few files indexes, and walk the graph to update some cache) - pushing a few revisions (read and write changelog, manifest and few files indexes, walk the graph to update some cache, performs various accesses locally and remotely during discovery) Benchmarks were run using the default module policy (c+py) and the rust one. No significant difference were found between the two implementation, so we will present result using the default policy (unless otherwise specified). I ran them on a few repositories : - mercurial: a "public changeset only" copy of mercurial from 2018-08-01 using zstd compression and sparse-revlog - pypy: a copy of pypy from 2018-08-01 using zstd compression and sparse-revlog - netbeans: a copy of netbeans from 2018-08-01 using zstd compression and sparse-revlog - mozilla-try: a copy of mozilla-try from 2019-02-18 using zstd compression and sparse-revlog - mozilla-try persistent-nodemap: Same as the above but with a persistent nodemap. Used for the log --patch benchmark only # Results For the smaller repositories (mercurial, pypy), the impact of mmap is almost imperceptible, other cost dominating the operation. The impact of prepopulating is undiscernible in the benchmark we ran. For larger repositories the benchmark support explanation given above: On netbeans, the log can be about 1% faster without repopulation (for a difference < 100ms) but unbundle becomes a bit slower, even when small. ### data-env-vars.name = netbeans-2018-08-01-zstd-sparse-revlog # benchmark.name = hg.command.unbundle # benchmark.variants.issue6528 = disabled # benchmark.variants.reuse-external-delta-parent = yes # benchmark.variants.revs = any-1-extra-rev # benchmark.variants.source = unbundle # benchmark.variants.verbosity = quiet with-populate: 0.240157 no-populate: 0.265087 (+10.38%, +0.02) # benchmark.variants.revs = any-100-extra-rev with-populate: 1.459518 no-populate: 1.481290 (+1.49%, +0.02) ## benchmark.name = hg.command.push # benchmark.variants.explicit-rev = none # benchmark.variants.issue6528 = disabled # benchmark.variants.protocol = ssh # benchmark.variants.reuse-external-delta-parent = yes # benchmark.variants.revs = any-1-extra-rev with-populate: 0.771919 no-populate: 0.792025 (+2.60%, +0.02) # benchmark.variants.revs = any-100-extra-rev with-populate: 1.459518 no-populate: 1.481290 (+1.49%, +0.02) For mozilla-try, the "slow down" from pre-populate for small `hg log` is more visible, but still small in absolute time. (using rust value for the persistent nodemap value to be relevant). ### data-env-vars.name = mozilla-try-2019-02-18-ds2-pnm # benchmark.name = hg.command.log # bin-env-vars.hg.flavor = rust # benchmark.variants.patch = yes # benchmark.variants.limit-rev = 1 with-populate: 0.237813 no-populate: 0.229452 (-3.52%, -0.01) # benchmark.variants.limit-rev = 10 # benchmark.variants.patch = yes with-populate: 1.213578 no-populate: 1.205189 ### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog # benchmark.variants.limit-rev = 1000 # benchmark.variants.patch = no # benchmark.variants.rev = tip with-populate: 0.198607 no-populate: 0.195038 (-1.80%, -0.00) However pre-populating provide a significant boost on more complex operations like unbundle or push: ### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog # benchmark.name = hg.command.push # benchmark.variants.explicit-rev = none # benchmark.variants.issue6528 = disabled # benchmark.variants.protocol = ssh # benchmark.variants.reuse-external-delta-parent = yes # benchmark.variants.revs = any-1-extra-rev with-populate: 4.798632 no-populate: 4.953295 (+3.22%, +0.15) # benchmark.variants.revs = any-100-extra-rev with-populate: 4.903618 no-populate: 5.014963 (+2.27%, +0.11) ## benchmark.name = hg.command.unbundle # benchmark.variants.revs = any-1-extra-rev with-populate: 1.423411 no-populate: 1.585365 (+11.38%, +0.16) # benchmark.variants.revs = any-100-extra-rev with-populate: 1.537909 no-populate: 1.688489 (+9.79%, +0.15)

win32mbcs: use str for encoding value This was reported to the TortoiseHg tracker as: https://foss.heptapod.net/mercurial/tortoisehg/thg/-/issues/5980 It doesn't look like we have any tests for this extension, but the explicit type hints are enough to convince pytype that the module level `_encoding` attr is str. The `encode()` and `decode()` methods are too complex to add type hints for them.

typing: add a trivial type hint to `mercurial/vfs.py` Since hg 3dbc7b1ecaba, pytype stopped seeing the return value of `rmtree` as `None`, and substituted `Any`.