Mercurial > hg
view tests/test-propertycache.py.out @ 27475:a2e2a8fa5fd1
revlog: avoid string slice when decompressing u* chunks
Revlog chunks can be stored uncompressed. If the first byte of the
raw data is \0, we store the data as is. Else we prefix it with 'u'.
Before, we performed a string slice to strip out the 'u' prefix.
With this patch, we use a buffer to avoid an extra memory copy and
associated garbage collection overhead.
I was unable to verify any performance impact of this patch. For both
mozilla-central and the hg repos, the number of manifest revisions
with 'u' prefixes is very small - under 1%. So this change likely
isn't called enough to have an impact on manifest reading. However,
the reasoning behind this change is solid, so it should be safe.
author | Gregory Szorc <gregory.szorc@gmail.com> |
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date | Sun, 20 Dec 2015 16:00:27 -0800 |
parents | 9789670992d6 |
children |
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=== property cache === calllog: [] cached value (unfiltered): NOCACHE = first access on unfiltered, should do a call access: 0 calllog: [0] cached value (unfiltered): 0 = second access on unfiltered, should not do call access 0 calllog: [0] cached value (unfiltered): 0 = first access on "visible" view, should do a call cached value ("visible" view): NOCACHE access: 7 calllog: [0, 7] cached value (unfiltered): 0 cached value ("visible" view): 7 = second access on "visible view", should not do call access: 7 calllog: [0, 7] cached value (unfiltered): 0 cached value ("visible" view): 7 = no effect on other view cached value ("immutable" view): NOCACHE access: 9 calllog: [0, 7, 9] cached value (unfiltered): 0 cached value ("visible" view): 7 cached value ("immutable" view): 9 === unfiltered property cache === unficalllog: [] cached value (unfiltered): NOCACHE cached value ("visible" view): NOCACHE cached value ("immutable" view): NOCACHE = first access on unfiltered, should do a call access (unfiltered): 100 unficalllog: [100] cached value (unfiltered): 100 = second access on unfiltered, should not do call access (unfiltered): 100 unficalllog: [100] cached value (unfiltered): 100 = access on view should use the unfiltered cache access (unfiltered): 100 access ("visible" view): 100 access ("immutable" view): 100 unficalllog: [100] cached value (unfiltered): 100 cached value ("visible" view): NOCACHE cached value ("immutable" view): NOCACHE = even if we clear the unfiltered cache cached value (unfiltered): NOCACHE cached value ("visible" view): NOCACHE cached value ("immutable" view): NOCACHE unficalllog: [100] access ("visible" view): 100 unficalllog: [100, 100] cached value (unfiltered): 100 cached value ("visible" view): NOCACHE cached value ("immutable" view): NOCACHE access ("immutable" view): 100 unficalllog: [100, 100] cached value (unfiltered): 100 cached value ("visible" view): NOCACHE cached value ("immutable" view): NOCACHE access (unfiltered): 100 unficalllog: [100, 100] cached value (unfiltered): 100 cached value ("visible" view): NOCACHE cached value ("immutable" view): NOCACHE