Mercurial > hg
view tests/test-wireproto-command-heads.t @ 47120:7109a38830c9
dirstate-tree: Fold "tracked descendants" counter update in main walk
For the purpose of implementing `has_tracked_dir` (which means "has tracked
descendants) without an expensive sub-tree traversal, we maintaing a counter
of tracked descendants on each "directory" node of the tree-shaped dirstate.
Before this changeset, mutating or inserting a node at a given path would
involve:
* Walking the tree from root through ancestors to find the node or the spot
where to insert it
* Looking at the previous node if any to decide what counter update is needed
* Performing any node mutation
* Walking the tree *again* to update counters in ancestor nodes
When profiling `hg status` on a large repo, this second walk takes times
while loading a the dirstate from disk.
It turns out we have enough information to decide before he first tree walk
what counter update is needed. This changeset merges the two walks, gaining
~10% of the total time for `hg update` (in the same hyperfine benchmark as
the previous changeset).
---
Profiling was done by compiling with this `.cargo/config`:
[profile.release]
debug = true
then running with:
py-spy record -r 500 -n -o /tmp/hg.json --format speedscope -- \
./hg status -R $REPO --config experimental.dirstate-tree.in-memory=1
then visualizing the recorded JSON file in https://www.speedscope.app/
Differential Revision: https://phab.mercurial-scm.org/D10554
author | Simon Sapin <simon.sapin@octobus.net> |
---|---|
date | Fri, 30 Apr 2021 14:22:14 +0200 |
parents | a732d70253b0 |
children |
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$ . $TESTDIR/wireprotohelpers.sh $ hg init server $ enablehttpv2 server $ cd server $ hg debugdrawdag << EOF > H I J > | | | > E F G > | |/ > C D > |/ > B > | > A > EOF $ hg phase --force --secret J $ hg phase --public E $ hg log -r 'E + H + I + G + J' -T '{rev}:{node} {desc} {phase}\n' 4:78d2dca436b2f5b188ac267e29b81e07266d38fc E public 7:ae492e36b0c8339ffaf328d00b85b4525de1165e H draft 8:1d6f6b91d44aaba6d5e580bc30a9948530dbe00b I draft 6:29446d2dc5419c5f97447a8bc062e4cc328bf241 G draft 9:dec04b246d7cbb670c6689806c05ad17c835284e J secret $ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log $ cat hg.pid > $DAEMON_PIDS All non-secret heads returned by default $ sendhttpv2peer << EOF > command heads > EOF creating http peer for wire protocol version 2 sending heads command response: [ b'\x1dok\x91\xd4J\xab\xa6\xd5\xe5\x80\xbc0\xa9\x94\x850\xdb\xe0\x0b', b'\xaeI.6\xb0\xc83\x9f\xfa\xf3(\xd0\x0b\x85\xb4R]\xe1\x16^', b')Dm-\xc5A\x9c_\x97Dz\x8b\xc0b\xe4\xcc2\x8b\xf2A' ] Requesting just the public heads works $ sendhttpv2peer << EOF > command heads > publiconly 1 > EOF creating http peer for wire protocol version 2 sending heads command response: [ b'x\xd2\xdc\xa46\xb2\xf5\xb1\x88\xac&~)\xb8\x1e\x07&m8\xfc' ] $ cat error.log