Hi WebKittens!
Recently, node-jsc is announced[1]. When I read the documents of that
project,
I found that they use LLInt ASM interpreter instead of CLoop in non-JIT
environment.
So I had one question in my mind: How fast the LLInt ASM interpreter when
comparing to CLoop?
I've set up two builds. One is CLoop build (-DENABLE_JIT=OFF) and another
is JIT build JSC with `JSC_useJIT=false`.
And I've ran kraken benchmarks with these two builds in x64 Linux machine.
The results are the followings.
Benchmark report for Kraken on sakura-trick.
VMs tested:
"baseline" at
/home/yusukesuzuki/dev/WebKit/WebKitBuild/nojit/Release/bin/jsc
"patched" at
/home/yusukesuzuki/dev/WebKit/WebKitBuild/nojit-llint/Release/bin/jsc
Collected 10 samples per benchmark/VM, with 10 VM invocations per
benchmark. Emitted a call to gc() between sample
measurements. Used 1 benchmark iteration per VM invocation for warm-up.
Used the jsc-specific preciseTime()
function to get microsecond-level timing. Reporting benchmark execution
times with 95% confidence intervals in
milliseconds.
baseline
patched
ai-astar 3619.974+-57.095 ^
2014.835+-59.016 ^ definitely 1.7967x faster
audio-beat-detection 1762.085+-24.853 ^
1030.902+-19.743 ^ definitely 1.7093x faster
audio-dft 1822.426+-28.704 ^
909.262+-16.640 ^ definitely 2.0043x faster
audio-fft 1651.070+-9.994 ^
865.203+-7.912 ^ definitely 1.9083x faster
audio-oscillator 1853.697+-26.539 ^
992.406+-12.811 ^ definitely 1.8679x faster
imaging-darkroom 2118.737+-23.219 ^
1303.729+-8.071 ^ definitely 1.6251x faster
imaging-desaturate 3133.654+-28.545 ^
1759.738+-18.182 ^ definitely 1.7808x faster
imaging-gaussian-blur 16321.090+-154.893 ^
7228.017+-58.508 ^ definitely 2.2580x faster
json-parse-financial 57.256+-2.876
56.101+-4.265 might be 1.0206x faster
json-stringify-tinderbox 38.470+-2.788 ?
38.771+-0.935 ?
stanford-crypto-aes 851.341+-7.738 ^
485.438+-13.904 ^ definitely 1.7538x faster
stanford-crypto-ccm 556.133+-6.606 ^
264.161+-3.970 ^ definitely 2.1053x faster
stanford-crypto-pbkdf2 1945.718+-15.968 ^
1075.013+-13.337 ^ definitely 1.8099x faster
stanford-crypto-sha256-iterative 623.203+-7.604 ^
349.782+-12.810 ^ definitely 1.7817x faster
<arithmetic> 2596.775+-14.857 ^
1312.383+-8.840 ^ definitely 1.9787x faster
Surprisingly, LLInt ASM interpreter is significantly faster than CLoop. I
expected it would be fast, but it would show around 10% performance win.
But the reality is that it is 2x faster. It is too much number to me to
consider enabling LLInt ASM interpreter for non-JIT build configuration.
As a bonus, LLInt ASM interpreter offers sampling profiler support even in
non-JIT environment.
So my proposal is, how about enabling LLInt ASM interpreter in non-JIT
configuration environment in major architectures (x64 and ARM64)?
Best regards,
Yusuke Suzuki
[1]:
https://lists.webkit.org/pipermail/webkit-dev/2018-September/030140.html
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