484584 - peacekeeper test case slower when traced successfully

Status: RESOLVED DUPLICATE of bug 479110

(Core :: JavaScript Engine, defect)

Description

[Robert Sayre]

Attachment: peacekeeper.arrayCombined.js

The attachment on the tracemonkey branch is slower than mozilla-central.

Comment 1

[Robert Sayre]

Attachment: Shark profile showing js_MonitorLoopEdge costs

Comment 2

[Robert Sayre]

tracemonkey JIT:         8475 ops/sec
tracemonkey no-JIT:      9000 ops/sec
mozilla-central no-JIT:  9050 ops/sec
mozilla-central JIT:     10450 ops/sec

Comment 3

[Robert Sayre]

Attachment: tracevis png

Comment 4

[Andreas Gal :gal]

Good testcase & analysis data. Thanks.

Comment 5

[Andreas Gal :gal]

Cause: massive side-exits. You can easily see this with TRACEMONKEY=stats in the shell:

recorder: started(5), aborted(3), completed(2), different header(0), trees trashed(0), slot promoted(0), unstable loop variable(0), breaks(0), returns(0), unstableInnerCalls(0)
monitor: triggered(121177), exits(121177), type mismatch(0), global mismatch(0)

Comment 6

[Andreas Gal :gal]

whale:src gal$ TRACEMONKEY=stats ./Darwin_DBG.OBJ/js -j x.js
benchmark.runTest Start running test.
benchmark Elapsed time 1077. Operations: 10000. Operations per second: 9285.051067780872
recorder: started(4), aborted(1), completed(4), different header(0), trees trashed(0), slot promoted(0), unstable loop variable(0), breaks(0), returns(0), unstableInnerCalls(0)
monitor: triggered(6), exits(6), type mismatch(0), global mismatch(0)

Yep, this is a dup (note: score is for a debug build here).

Comment 8

[Andreas Gal :gal]

OPT scores with mismatch patch applied:

benchmark.runTest Start running test.
benchmark Elapsed time 679. Operations: 10000. Operations per second: 14727.540500736375
whale:src gal$ ./Darwin_OPT.OBJ/js x.js
benchmark.runTest Start running test.
benchmark Elapsed time 1043. Operations: 10000. Operations per second: 9587.727708533079
whale:src gal$ 

The rest is array overhead in join.