1477632 - Always inline PLDHashTable::SearchTable()

Status: RESOLVED FIXED

(Core :: XPCOM, enhancement)

Description

[Nicholas Nethercote [inactive]]

It's super hot.

Comment 1

[Nicholas Nethercote [inactive]]

Attachment: Bug 1477632 - Always inline PLDHashTable::SearchTable().

This speeds up BenchCollections.PLDHash as follows:

>     succ_lookups      fail_lookups     insert_remove           iterate
>          42.8 ms           51.6 ms           21.0 ms           34.9 ms
>          41.8 ms           51.9 ms           20.0 ms           34.6 ms
>          41.6 ms           51.3 ms           19.3 ms           34.5 ms
>          41.6 ms           51.3 ms           19.8 ms           35.0 ms
>          41.7 ms           50.8 ms           20.5 ms           35.2 ms

After:

>     succ_lookups      fail_lookups     insert_remove           iterate
>          37.7 ms           33.1 ms           19.7 ms           35.0 ms
>          37.0 ms           32.5 ms           19.1 ms           35.4 ms
>          37.6 ms           33.6 ms           19.2 ms           36.2 ms
>          36.7 ms           33.3 ms           19.1 ms           35.3 ms
>          37.1 ms           33.1 ms           19.1 ms           35.0 ms

Successful lookups are about 1.13x faster, failing lookups are about 1.54x
faster, and insertions/removals are about 1.05x faster.

On Linux64, this increases the size of libxul (as measured by `size`) by a mere
16 bytes.

Review commit: https://reviewboard.mozilla.org/r/258738/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/258738/

Comment 2

[Nathan Froyd [:froydnj]]

Comment on attachment 8994118 [details]
Bug 1477632 - Always inline PLDHashTable::SearchTable().

https://reviewboard.mozilla.org/r/258738/#review265682

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/5da2166fd301
Always inline PLDHashTable::SearchTable(). r=froydnj

Comment 4

[Sebastian Hengst [:aryx] (needinfo on intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/5da2166fd301

Comment 5

[Nicholas Nethercote [inactive]]

Perfherder results are here:
https://treeherder.mozilla.org/perf.html#/graphs?series=mozilla-inbound,1730062,1,6&series=mozilla-central,1730148,1,6&series=mozilla-central,1730117,1,6&series=mozilla-central,1730160,1,6&series=mozilla-central,1730172,1,6

It's a clear win on linux32, but didn't appear to have much effect on other platforms. (Locally, it was a clear win on linux64 for me.)