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view tests/test-remotefilelog-gcrepack.t @ 42743:8c9a6adec67a
rust-discovery: using the children cache in add_missing
The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.
The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.
This is a case where staying on the same side of the interface
between the two languages has clear benefits.
On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.
For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:
Rust version with simple iteration
addcommons: 57.287us
first undecided computation: 184.278334ms
first children cache computation: 131.056us
addmissings iteration: 42.766us
first addinfo total: 185.24 ms
Python + C version
first addcommons: 0.29 ms
addcommons 0.21 ms
first undecided computation 191.35 ms
addmissings 45.75 ms
first addinfo total: 237.77 ms
On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:
Rust version:
first undecided computation: 293.842629ms
first children cache computation: 407.911297ms
addmissings iteration: 34.312869ms
first addinfo total: 776.02 ms
taking initial sample
query 2: sampling time: 1318.38 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings: 143.062us
Python + C version:
first undecided computation 298.13 ms
addmissings 80.13 ms
first addinfo total: 399.62 ms
taking initial sample
query 2: sampling time: 3957.23 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings 52.88 ms
Differential Revision: https://phab.mercurial-scm.org/D6428
author | Georges Racinet <georges.racinet@octobus.net> |
---|---|
date | Tue, 16 Apr 2019 01:16:39 +0200 |
parents | f22131315791 |
children | fac25de8cbec |
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#require no-windows $ . "$TESTDIR/remotefilelog-library.sh" $ hg init master $ cd master $ cat >> .hg/hgrc <<EOF > [remotefilelog] > server=True > EOF $ echo x > x $ hg commit -qAm x $ echo y > y $ rm x $ hg commit -qAm DxAy $ echo yy > y $ hg commit -qAm y $ cd .. $ hgcloneshallow ssh://user@dummy/master shallow -q 1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob) # Set the prefetchdays config to zero so that all commits are prefetched # no matter what their creation date is. $ cd shallow $ cat >> .hg/hgrc <<EOF > [remotefilelog] > prefetchdays=0 > EOF $ cd .. # Prefetch all data and repack $ cd shallow $ cat >> .hg/hgrc <<EOF > [remotefilelog] > bgprefetchrevs=all() > EOF $ hg prefetch 2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob) $ hg repack $ sleep 0.5 $ hg debugwaitonrepack >/dev/null 2>%1 $ find $CACHEDIR | sort | egrep ".datapack|.histpack" $TESTTMP/hgcache/master/packs/7bcd2d90b99395ca43172a0dd24e18860b2902f9.histpack $TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37.datapack # Ensure that all file versions were prefetched $ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1` $TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37: x: Node Delta Base Delta Length Blob Size 1406e7411862 000000000000 2 2 Total: 2 2 (0.0% bigger) y: Node Delta Base Delta Length Blob Size 50dbc4572b8e 000000000000 3 3 076f5e2225b3 50dbc4572b8e 14 2 Total: 17 5 (240.0% bigger) # Test garbage collection during repack $ cat >> .hg/hgrc <<EOF > [remotefilelog] > bgprefetchrevs=tip > gcrepack=True > nodettl=86400 > EOF $ hg repack $ sleep 0.5 $ hg debugwaitonrepack >/dev/null 2>%1 $ find $CACHEDIR | sort | egrep ".datapack|.histpack" $TESTTMP/hgcache/master/packs/7bcd2d90b99395ca43172a0dd24e18860b2902f9.histpack $TESTTMP/hgcache/master/packs/a4e1d094ec2aee8a08a4d6d95a13c634cc7d7394.datapack # Ensure that file 'x' was garbage collected. It should be GCed because it is not in the keepset # and is old (commit date is 0.0 in tests). Ensure that file 'y' is present as it is in the keepset. $ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1` $TESTTMP/hgcache/master/packs/a4e1d094ec2aee8a08a4d6d95a13c634cc7d7394: y: Node Delta Base Delta Length Blob Size 50dbc4572b8e 000000000000 3 3 Total: 3 3 (0.0% bigger) # Prefetch all data again and repack for later garbage collection $ cat >> .hg/hgrc <<EOF > [remotefilelog] > bgprefetchrevs=all() > EOF $ hg prefetch 2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob) $ hg repack $ sleep 0.5 $ hg debugwaitonrepack >/dev/null 2>%1 $ find $CACHEDIR | sort | egrep ".datapack|.histpack" $TESTTMP/hgcache/master/packs/7bcd2d90b99395ca43172a0dd24e18860b2902f9.histpack $TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37.datapack # Ensure that all file versions were prefetched $ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1` $TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37: x: Node Delta Base Delta Length Blob Size 1406e7411862 000000000000 2 2 Total: 2 2 (0.0% bigger) y: Node Delta Base Delta Length Blob Size 50dbc4572b8e 000000000000 3 3 076f5e2225b3 50dbc4572b8e 14 2 Total: 17 5 (240.0% bigger) # Test garbage collection during repack. Ensure that new files are not removed even though they are not in the keepset # For the purposes of the test the TTL of a file is set to current time + 100 seconds. i.e. all commits in tests have # a date of 1970 and therefore to prevent garbage collection we have to set nodettl to be farther from 1970 than we are now. $ cat >> .hg/hgrc <<EOF > [remotefilelog] > bgprefetchrevs= > nodettl=$(($(date +%s) + 100)) > EOF $ hg repack $ sleep 0.5 $ hg debugwaitonrepack >/dev/null 2>%1 $ find $CACHEDIR | sort | egrep ".datapack|.histpack" $TESTTMP/hgcache/master/packs/7bcd2d90b99395ca43172a0dd24e18860b2902f9.histpack $TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37.datapack # Ensure that all file versions were prefetched $ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1` $TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37: x: Node Delta Base Delta Length Blob Size 1406e7411862 000000000000 2 2 Total: 2 2 (0.0% bigger) y: Node Delta Base Delta Length Blob Size 50dbc4572b8e 000000000000 3 3 076f5e2225b3 50dbc4572b8e 14 2 Total: 17 5 (240.0% bigger)