tags-cache: skip the filternode step if we are not going to use it When warming the hgtagsfnodescache, we don't need the actual result, so we can simply skip the part that "filter" fnode we read from the cache. So provide a quite visible speed up to the top level `hg debugupdatecache` function. ### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog # benchmark.name = hg.debug.debug-update-cache # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default # benchmark.variants.pre-state = warm before: 19.947581 after: 18.916804 (-5.17%, -1.03)

tags-cache: add a dedicated warm cache function to hgtagsfnodescache Having a dedicated API point will help to optimize that specific usage. Right doing a full phases weam takes a long time, even when the cache is already filled.

outgoing: add a simple fastpath when there is no common This further speed up case like `hg bundle --all` for larger repository. ### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog # benchmark.name = hg.command.bundle # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default # benchmark.variants.revs = all # benchmark.variants.type = none-streamv2 before: 316.749699 after: 311.165461 (-1.76%, -5.58) There is further work to be done in this area like not doing any outgoing computation in the stream case for example. however the recent changes already gives use a large win for a small amount of local work. ### benchmark.name = hg.command.bundle # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default # benchmark.variants.revs = all # benchmark.variants.type = none-streamv2 ## data-env-vars.name = mercurial-public-2024-03-22-zstd-sparse-revlog pre-%ln-change: 1.263859 the-%ln-change: 0.700229 (-44.60%, -0.56) prev-changeset: 0.496050 (-60.75%, -0.77) this-changeset: 0.495243 (-60.81%, -0.77) ## data-env-vars.name = tryton-public-2024-03-22-zstd-sparse-revlog pre-%ln-change: 2.975765 the-%ln-change: 1.870798 (-37.13%, -1.10) prev-changeset: 1.461583 (-50.88%, -1.51) this-changeset: 1.469185 (-50.63%, -1.51) ## data-env-vars.name = pypy-2024-03-22-zstd-sparse-revlog pre-%ln-change: 4.540080 the-%ln-change: 3.401700 (-25.07%, -1.14) prev-changeset: 2.915810 (-35.78%, -1.62) this-changeset: 2.911643 (-35.87%, -1.63) ## data-env-vars.name = heptapod-public-2024-03-25-zstd-sparse-revlog pre-%ln-change: 10.138396 the-%ln-change: 7.750458 (-23.55%, -2.39) prev-changeset: 6.665565 (-34.25%, -3.47) this-changeset: 6.672078 (-34.19%, -3.47) ## data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog pre-%ln-change: 399.484481 the-%ln-change: 346.508952 (-13.26%, -52.98) prev-changeset: 316.749699 (-20.71%, -82.73) this-changeset: 311.165461 (-22.11%, -88.32)

outgoing: rework the handling of the `missingroots` case to be faster The previous implementation was slow, to the point it was taking a significant amount of `hg bundle --type none-streamv2` call. We rework the code to compute the same value much faster, making the operation disappear from the `hg bundle --type none-streamv2` profile. Someone would remark that producing a streamclone does not requires an `outgoing` object. However that is a matter for another day. There is other user of `missingroots` (non stream `hg bundle` call for example), and they will also benefit from this rework. We implement an old TODO in the process, directly computing the missing and common attribute as we have most element at hand already. ### benchmark.name = hg.command.bundle # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default # benchmark.variants.revs = all # benchmark.variants.type = none-streamv2 ## data-env-vars.name = heptapod-public-2024-03-25-zstd-sparse-revlog before: 7.750458 after: 6.665565 (-14.00%, -1.08) ## data-env-vars.name = mercurial-public-2024-03-22-zstd-sparse-revlog before: 0.700229 after: 0.496050 (-29.16%, -0.20) ## data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog before: 346.508952 after: 316.749699 (-8.59%, -29.76) ## data-env-vars.name = pypy-2024-03-22-zstd-sparse-revlog before: 3.401700 after: 2.915810 (-14.28%, -0.49) ## data-env-vars.name = tryton-public-2024-03-22-zstd-sparse-revlog before: 1.870798 after: 1.461583 (-21.87%, -0.41) note: this whole `missingroots` of outgoing has a limited number of callers and could likely be replace by something simpler (like taking an explicit "missing_revs" set for example). However this is a wider change and we focus on a small impact, quick rework that does not change the API for now.

proxy-vfs: also proxy the `audit` attribute In the previous changeset, we had to do a little dance to access the useful `audit` attribute. We now provide a proper accessors to it. We don't update the code in `perf.py` because it has to remain compatible with older version of Mercurial. This will just be nicer in the future.

perf: clear vfs audit_cache before each run When generating a stream clone, we spend a large amount of time auditing path. Before this changes, the first run was warming the vfs cache for the other runs, leading to a large runtime difference and a "faulty" reported timing for the operation. We now clear this important cache between run to get a more realistic timing. Below are some example of median time change when clearing these cases. The maximum time for a run did not changed significantly. ### data-env-vars.name = mozilla-central-2018-08-01-zstd-sparse-revlog # benchmark.name = hg.perf.exchange.stream.generate # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default # benchmark.variants.version = latest no-clearing: 17.289905 cache-clearing: 21.587965 (+24.86%, +4.30) ## data-env-vars.name = mozilla-central-2024-03-22-zstd-sparse-revlog no-clearing: 32.670748 cache-clearing: 40.467095 (+23.86%, +7.80) ## data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog no-clearing: 37.838858 cache-clearing: 46.072749 (+21.76%, +8.23) ## data-env-vars.name = mozilla-unified-2024-03-22-zstd-sparse-revlog no-clearing: 32.969395 cache-clearing: 39.646209 (+20.25%, +6.68) In addition, this significantly reduce the timing difference between the performance command, from the perf extensions and a `real `hg bundle` call producing a stream bundle. Some significant differences remain especially on the "mozilla-try" repositories, but they are now smaller. Note that some of that difference will actually not be attributable to the stream generation (like maybe phases or branch map computation). Below are some benchmarks done on a currently draft changeset fixing some unrelated slowness in `hg bundle` (34a78972af409d1ff37c29e60f6ca811ad1a457d) ### data-env-vars.name = mozilla-central-2018-08-01-zstd-sparse-revlog # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default hg.perf.exchange.stream.generate: 21.587965 hg.command.bundle: 24.301799 (+12.57%, +2.71) ## data-env-vars.name = mozilla-central-2024-03-22-zstd-sparse-revlog hg.perf.exchange.stream.generate: 40.467095 hg.command.bundle: 44.831317 (+10.78%, +4.36) ## data-env-vars.name = mozilla-unified-2024-03-22-zstd-sparse-revlog hg.perf.exchange.stream.generate: 39.646209 hg.command.bundle: 45.395258 (+14.50%, +5.75) ## data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog hg.perf.exchange.stream.generate: 46.072749 hg.command.bundle: 55.882608 (+21.29%, +9.81) ## data-env-vars.name = mozilla-try-2023-03-22-zlib-general-delta hg.perf.exchange.stream.generate: 334.716708 hg.command.bundle: 377.856767 (+12.89%, +43.14) ## data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog hg.perf.exchange.stream.generate: 302.972301 hg.command.bundle: 326.098755 (+7.63%, +23.13)

perf: start recording total time after warming The warming might be costly and this should not affect the "time profile" of the actual collection.

perf: run the gc before each run The python garbage collector is a large source of performance troubles, we run it right before the timed section to reduce the change for the gc to add noise to the benchmark.

perf: allow profiling of more than one run By default, we still profile the first run only. However profiling more run help to understand side effect from one run to the other. So we add an option to be able to do so.

profiler: flush after writing the profiler output Otherwise, the profiler output might only partially appears until the next flush of the buffer. Since profiling often happens for long operation, the next flush can be a long time away.