CODEWITHSUNDEEP
javascriptjitv8
rames
rames

Reputation: 261

Building v8 without JIT

I would like to run some tests on v8 with and without JIT to compare performances. I know JIT will improve my average speed performance, but it would be nice for me to have some actual more detailed tests results as I want to work with mobile platforms.

I haven't found how to enable or disable JIT like it exists on Squirrelfish (cf. ENABLE_JIT in JavaScriptCore/wtf/Platform.h).

Does somebody knows how to do that with v8?

Thanks.

Alexandre

Upvotes: 12

Views: 3051

Answers (2)

Erik Corry
Erik Corry

Reputation: 254

On a 32 bit little endian platform you can build with the ARM simulator. This is a testing feature and performance will be terrible, but it does work and involves no direct execution of JITed code. Use the --simulator=arm option on the scons or test.py command line.

Upvotes: 2

rames
rames

Reputation: 261

For those who may be interested I got the following answer from Søren Gjesse on v8-users google groups.

Hi, It is not possible to disable dynamically generated code in V8. Unlike other JavaScript engines V8 does not have an interpreter mode - it always generates native code.

One exception is the RegExp engine which have an interpreter and native code version. The compile time define V8_NATIVE_REGEXP enables generating native code for RegExp processing.

Regards, Søren

Upvotes: 14

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