Drew Ritter created THRIFT-4592:
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Summary: JS: readI32 performance on large arrays is very poor in
Chrome
Key: THRIFT-4592
URL: https://issues.apache.org/jira/browse/THRIFT-4592
Project: Thrift
Issue Type: Bug
Components: JavaScript - Library
Affects Versions: 0.11.0
Environment: Tested in Chrome 67.0.3396.87 and Safari 11.1.1
(13605.2.8) on OSX.
Reporter: Drew Ritter
Attachments: ThriftBenchmarker.js, readI32_pop.patch
`readI32` (
[https://github.com/apache/thrift/blob/master/lib/js/src/thrift.js#L1311-L1341]
) performance is extremely poor in Chrome when reading values from large
arrays. This is due to the use of Array.shift (
[https://github.com/apache/thrift/blob/master/lib/js/src/thrift.js#L1322] )
which seems to have performance issues in V8/Chrome.
As Chrome is a high market share browser I propose either changing this to use
reverse/pop or detect the appropriate strategy given array length. I think this
is due to how V8 handles large arrays and the heuristics used to determine
whether data should be stored in a C-backed array or hash map.
STR:
0) Download or copy the attached ThriftBenchmarker.js - this file has some
helper functions to build large arrays, as well as a copy/paste of the current
`readI32` as well as one that uses Array.reverse/Array.pop over Array.shift.
1) Run this test in Chrome - you can simply copy/paste the code into the
Console.
2) Observe that the tests using Array.shift are quite slow in Chrome:
{code:java}
-- testing long arrays --
shift test: 1084.566162109375ms
pop test: 37.604248046875ms
-- testing long arrays of strings --
shift test: 5189.416015625ms
pop test: 17.9189453125ms
-- testing short arrays --
shift test: 0.06005859375ms
pop test: 0.016845703125ms
-- testing short arrays of strings --
shift test: 0.01611328125ms
pop test: 0.01318359375ms{code}
3) Run this test in Safari (or a non-V8) browser.
4) Observe that the tests using Array.shift are far faster:
{code:java}
-- testing long arrays --
shift test: 19.235ms
pop test: 11.774ms
- testing long arrays of strings --
shift test: 13.087ms
pop test: 12.805ms
- testing short arrays --
shift test: 0.049ms
pop test: 0.054ms
- testing short arrays of strings --
shift test: 0.039ms
pop test: 0.022ms{code}
[^ThriftBenchmarker.js]
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