5 ms·

V8 performance can beat C sometimes

46 points by pmelendez 13y ago

jonrx 13y ago
Congralutations! :-) (And the program is IMHO clearer than the C implementation)
- pmelendez 13y ago
  To the V8 team and the implementer of the testing program. Disclaimer: I had anything to do with this, I just thought it was interesting enough to post it.
NathanKP 13y ago
The code for the C implementation is incredibly verbose compared to the code for the JS implementation. JS: http://benchmarksgame.alioth.debian.org/u64/program.php?test=regexdna&lang=v8&id=2 http://benchmarksgame.alioth.debian.org/u64/program.php?test... C: http://benchmarksgame.alioth.debian.org/u64/program.php?test=regexdna&lang=gcc&id=1 http://benchmarksgame.alioth.debian.org/u64/program.php?test...
- unwind 13y ago
  That's just ... absurd, in comparison at least. It uses TCL and glib?! I'll go out on a limb here and claim that this C program is not the shortest possible equivalent to the JS version.
  - igouy 13y ago
    That isn't the only C program shown :-) http://benchmarksgame.alioth.debian.org/u64/program.php?test=regexdna&lang=gcc&id=4 http://benchmarksgame.alioth.debian.org/u64/program.php?test... http://benchmarksgame.alioth.debian.org/u64/program.php?test=regexdna&lang=gcc&id=2 http://benchmarksgame.alioth.debian.org/u64/program.php?test...
majke 13y ago
If I read this benchmark right: v8 regexps are faster than TCL regexps. Hardly surprising.
- pmelendez 13y ago
  I also beats all the other regexps engines though.
  - kevingadd 13y ago
    Likely because V8 only works on platforms where JIT is possible, so the regex engine relies on JITting specialized native code for the regex. A portable C/C++ regex library can't really do that.
detrino 13y ago
No this is not V8 performance beating C. This is V8 calling a regexp library written in C++. C just happens to be using a different library that is slower.
- pmelendez 13y ago
  >"This is V8 calling a regexp library written in C++" But it also beat the C++ implementation though.
  - detrino 13y ago
    I guess that re2 (the library that this C++ code is using) is slower than irregexp (the library that V8 is uses) on this benchmark.
lambda 13y ago
This isn't V8 beating C; this is one regex library being faster than another (both written in C or C++).
- pmelendez 13y ago
  As far as I know Irregexp[1] compiles on V8 byte code so you can't use it isolated without V8. Please, let me know if you find the opposite. [1] http://blog.chromium.org/2009/02/irregexp-google-chromes-new-regexp.html http://blog.chromium.org/2009/02/irregexp-google-chromes-new...
  - z92 13y ago
    > Irregexp[1] compiles on V8 byte code I was thinking: but V8 doesn't have byte code. Then opened the link: "After optimization we generate native machine code which uses backtracking to try different alternatives."
    - pmelendez 13y ago
      Well I might got it wrong but I got the bytecode reference from here: http://v8.googlecode.com/svn/trunk/src/interpreter-irregexp.cc http://v8.googlecode.com/svn/trunk/src/interpreter-irregexp.... Skimming the code it does look like they are interpreting byte code from Irregexp but I would need to read further to say it for sure.
    - ahomescu1 13y ago
      It's not JavaScript bytecode, but regex bytecode. V8 parses regular expressions to regex ASTs, takes them through some more intermediate forms, then finally to a special regex bytecode. That bytecode is either interpreted, or JIT compiled (depending of some build options, I think). You can look at a list of bytecodes in [1], and at the x64 JIT in [2]. 1 - http://code.google.com/p/v8/source/browse/trunk/src/bytecodes-irregexp.h http://code.google.com/p/v8/source/browse/trunk/src/bytecode... 2 - http://code.google.com/p/v8/source/browse/trunk/src/x64/regexp-macro-assembler-x64.cc http://code.google.com/p/v8/source/browse/trunk/src/x64/rege...
- 13y ago
deleted 13y ago
[deleted]
jwineinger 13y ago
The V8 version used nearly 50% more memory than the C version. It is well known that you can often get faster execution times at the cost of increased memory usage.
- igouy 13y ago
  More like 30%
anjanb 13y ago
why is golang so much slower compared to Java ? Is it because the language is immature or because the language libraries are immature ?
- chimeracoder 13y ago
  Go not only uses a different library for processing regular expressions, but a different algorithm altogether. It is slower in some cases than the standard PCRE implementations but faster in others. http://code.google.com/p/re2/ http://code.google.com/p/re2/
  - igouy 13y ago
    Go program using PCRE http://benchmarksgame.alioth.debian.org/u64/program.php?test=regexdna&lang=go&id=8 http://benchmarksgame.alioth.debian.org/u64/program.php?test...
jonnii 13y ago
Quickly, everyone convert their C to javascript!
danso 13y ago
Anyone else read this as "VB" as in, "Visual Basic"? Now that I would bookmark :)
- vezzy-fnord 13y ago
  Yes, I got the same impression.
jbverschoor 13y ago
So ruby java lua and python are all about the same?
varelse 13y ago
Rather than argue back and forth about which regex implementation is better here, I'd simply note the absence of multicore numbers for V8 and that the crappy Tcl library beats single-threaded Javascript when run multicore. It would be interesting, however, to compare the performance here to that of the "grep" command on the same expressions. I'd be surprised at anything short of a total smackdown of Javascript V8. I would expect an even bigger smackdown if one invoked GPUs: http://bkase.github.io/CUDA-grep/finalreport.html http://bkase.github.io/CUDA-grep/finalreport.html Even more interesting would be an OpenCL implementation that did exactly what V8 is doing to the regexes (Why? Because it can). And total aside, this is why I don't participate in TopCoder competitions - they never let you have any real fun.
- _random_ 13y ago
  The idea was obviously to pick a test and environment that would make it look like V8 can beat something other than interpreted JS. Otherwise it would've been the complete package: string manipulation, numerical computation, multi-core etc.

46 points by pmelendez 13y ago

jonrx 13y ago

Congralutations! :-) (And the program is IMHO clearer than the C implementation)

pmelendez 13y ago
To the V8 team and the implementer of the testing program. Disclaimer: I had anything to do with this, I just thought it was interesting enough to post it.

NathanKP 13y ago

The code for the C implementation is incredibly verbose compared to the code for the JS implementation. JS: http://benchmarksgame.alioth.debian.org/u64/program.php?test=regexdna&lang=v8&id=2 http://benchmarksgame.alioth.debian.org/u64/program.php?test... C: http://benchmarksgame.alioth.debian.org/u64/program.php?test=regexdna&lang=gcc&id=1 http://benchmarksgame.alioth.debian.org/u64/program.php?test...

unwind 13y ago
That's just ... absurd, in comparison at least. It uses TCL and glib?! I'll go out on a limb here and claim that this C program is not the shortest possible equivalent to the JS version.
- igouy 13y ago
  That isn't the only C program shown :-) http://benchmarksgame.alioth.debian.org/u64/program.php?test=regexdna&lang=gcc&id=4 http://benchmarksgame.alioth.debian.org/u64/program.php?test... http://benchmarksgame.alioth.debian.org/u64/program.php?test=regexdna&lang=gcc&id=2 http://benchmarksgame.alioth.debian.org/u64/program.php?test...

majke 13y ago

If I read this benchmark right: v8 regexps are faster than TCL regexps. Hardly surprising.

pmelendez 13y ago
I also beats all the other regexps engines though.
- kevingadd 13y ago
  Likely because V8 only works on platforms where JIT is possible, so the regex engine relies on JITting specialized native code for the regex. A portable C/C++ regex library can't really do that.

detrino 13y ago

No this is not V8 performance beating C. This is V8 calling a regexp library written in C++. C just happens to be using a different library that is slower.

pmelendez 13y ago
>"This is V8 calling a regexp library written in C++" But it also beat the C++ implementation though.
- detrino 13y ago
  I guess that re2 (the library that this C++ code is using) is slower than irregexp (the library that V8 is uses) on this benchmark.

lambda 13y ago

This isn't V8 beating C; this is one regex library being faster than another (both written in C or C++).

pmelendez 13y ago
As far as I know Irregexp[1] compiles on V8 byte code so you can't use it isolated without V8. Please, let me know if you find the opposite. [1] http://blog.chromium.org/2009/02/irregexp-google-chromes-new-regexp.html http://blog.chromium.org/2009/02/irregexp-google-chromes-new...
- z92 13y ago
  > Irregexp[1] compiles on V8 byte code I was thinking: but V8 doesn't have byte code. Then opened the link: "After optimization we generate native machine code which uses backtracking to try different alternatives."
  - pmelendez 13y ago
    Well I might got it wrong but I got the bytecode reference from here: http://v8.googlecode.com/svn/trunk/src/interpreter-irregexp.cc http://v8.googlecode.com/svn/trunk/src/interpreter-irregexp.... Skimming the code it does look like they are interpreting byte code from Irregexp but I would need to read further to say it for sure.
  - ahomescu1 13y ago
    It's not JavaScript bytecode, but regex bytecode. V8 parses regular expressions to regex ASTs, takes them through some more intermediate forms, then finally to a special regex bytecode. That bytecode is either interpreted, or JIT compiled (depending of some build options, I think). You can look at a list of bytecodes in [1], and at the x64 JIT in [2]. 1 - http://code.google.com/p/v8/source/browse/trunk/src/bytecodes-irregexp.h http://code.google.com/p/v8/source/browse/trunk/src/bytecode... 2 - http://code.google.com/p/v8/source/browse/trunk/src/x64/regexp-macro-assembler-x64.cc http://code.google.com/p/v8/source/browse/trunk/src/x64/rege...
13y ago

deleted 13y ago

[deleted]

jwineinger 13y ago

The V8 version used nearly 50% more memory than the C version. It is well known that you can often get faster execution times at the cost of increased memory usage.

igouy 13y ago
More like 30%

anjanb 13y ago

why is golang so much slower compared to Java ? Is it because the language is immature or because the language libraries are immature ?

chimeracoder 13y ago
Go not only uses a different library for processing regular expressions, but a different algorithm altogether. It is slower in some cases than the standard PCRE implementations but faster in others. http://code.google.com/p/re2/ http://code.google.com/p/re2/
- igouy 13y ago
  Go program using PCRE http://benchmarksgame.alioth.debian.org/u64/program.php?test=regexdna&lang=go&id=8 http://benchmarksgame.alioth.debian.org/u64/program.php?test...

jonnii 13y ago

Quickly, everyone convert their C to javascript!

danso 13y ago

Anyone else read this as "VB" as in, "Visual Basic"? Now that I would bookmark :)

vezzy-fnord 13y ago
Yes, I got the same impression.

jbverschoor 13y ago

So ruby java lua and python are all about the same?

varelse 13y ago

Rather than argue back and forth about which regex implementation is better here, I'd simply note the absence of multicore numbers for V8 and that the crappy Tcl library beats single-threaded Javascript when run multicore. It would be interesting, however, to compare the performance here to that of the "grep" command on the same expressions. I'd be surprised at anything short of a total smackdown of Javascript V8. I would expect an even bigger smackdown if one invoked GPUs: http://bkase.github.io/CUDA-grep/finalreport.html http://bkase.github.io/CUDA-grep/finalreport.html Even more interesting would be an OpenCL implementation that did exactly what V8 is doing to the regexes (Why? Because it can). And total aside, this is why I don't participate in TopCoder competitions - they never let you have any real fun.

_random_ 13y ago
The idea was obviously to pick a test and environment that would make it look like V8 can beat something other than interpreted JS. Otherwise it would've been the complete package: string manipulation, numerical computation, multi-core etc.