[llvm-dev] MCJit Runtine Performance

[Morten Brodersen via llvm-dev]

Thanks Lang.

We are working on it (test-cases + ideas proposed by people on this list).

The production/optimization guys have to do this in-between customer 
work. And a single realistic run takes hours. So progress is steady but 
not fast.

I will report results on llvm-dev when we have them.

Cheers
Morten

On 13/02/16 05:32, Lang Hames wrote:
> Thanks Morten,
>
> I'll check this out and confirm that these optimization options are 
> being plumbed through as expected.
>
> Were you able to produce any test-cases that demonstrate the slow-down 
> in the end?
>
> - Lang.
>
> On Sun, Feb 7, 2016 at 5:00 PM, Morten Brodersen 
> <Morten.Brodersen at constrainttec.com 
> <mailto:Morten.Brodersen at constrainttec.com>> wrote:
>
>     Hi Lang,
>
>     > can you share your EngineBuilder configuration lines?
>
>     Sure.
>
>     The 3.5.2 version use:
>
>             llvm::ExecutionEngine* ee =
>                 llvm::EngineBuilder(module)
>     .setEngineKind(llvm::EngineKind::JIT)
>     .setOptLevel(llvm::CodeGenOpt::Aggressive)
>                     .create();
>
>     module->setDataLayout(ee->getTargetMachine()->getDataLayout());
>
>     And the 3.7.1 version use:
>
>             llvm::EngineBuilder builder(move(modulePtr));
>
>     builder.setEngineKind(llvm::EngineKind::JIT);
>             builder.setErrorStr(&error);
>     builder.setOptLevel(llvm::CodeGenOpt::Aggressive);
>
>             llvm::ExecutionEngine* ee = builder.create();
>
>     module->setDataLayout(*ee->getTargetMachine()->getDataLayout());
>
>     Cheers
>     Morten
>
>
>     On 05/02/16 19:13, Lang Hames wrote:
>>     Hi Morten,
>>
>>     Something else just occurred to me: can you share your
>>     EngineBuilder configuration lines?
>>     (http://llvm.org/docs/doxygen/html/classllvm_1_1EngineBuilder.html)
>>
>>     In particular - are you explicitly setting the optimization
>>     level? The old JIT may have had a different default.
>>
>>     - Lang.
>>
>>
>>
>>     Sent from my iPad
>>
>>     On Feb 4, 2016, at 10:54 PM, Jim Grosbach via llvm-dev
>>     <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
>>
>>>     I agree with Lang and Keno here. This is both unexpected and
>>>     very interesting. Given the differences in defaults between the
>>>     two, I would have expected the new JIT to have better
>>>     performance but longer compile times. That you are seeing the
>>>     opposite implies there is something very wrong and I'm very
>>>     interested to help figure out what it is.
>>>
>>>     Sent from my iPad
>>>
>>>     On Feb 4, 2016, at 9:12 PM, Morten Brodersen via llvm-dev
>>>     <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
>>>
>>>>     Hi Keno,
>>>>
>>>>     I am talking about runtime. The performance of the generated
>>>>     machine code. Not the time it takes to lower the IR to machine
>>>>     code.
>>>>
>>>>     We typically only JIT once (taking a few secs) and then run the
>>>>     generated machine code for hours. So the JIT time (IR ->
>>>>     machine code) doesn't impact us.
>>>>
>>>>     Cheers
>>>>     Morten
>>>>
>>>>     On 05/02/16 15:58, Keno Fischer wrote:
>>>>>     Actually, reading over all of this again, I realize I may have
>>>>>     made the wrong statement. The runtime regressions we see in
>>>>>     julia are actually regressions in how long LLVM itself takes
>>>>>     to do the compilation (but since it happens at run time in the
>>>>>     JIT case, I think of it as a regression in our running time).
>>>>>     We have only noticed occasional regressions in the performance
>>>>>     of the generated code (which we are in the process of fixing).
>>>>>     Which kind of regression are you talking about, time taken by
>>>>>     LLVM or time taken by the LLVM-generated code?
>>>>>
>>>>>     On Thu, Feb 4, 2016 at 11:44 PM, Rafael Espíndola
>>>>>     <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
>>>>>
>>>>>         On 4 February 2016 at 22:48, Morten Brodersen via llvm-dev
>>>>>         <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>>
>>>>>         wrote:
>>>>>         > Hi Rafael,
>>>>>         >
>>>>>         > Not easily (llc).
>>>>>         >
>>>>>         > Is there a way to make MCJit not use the large code
>>>>>         model when JIT'ing?
>>>>>         >
>>>>>
>>>>>         I think Davide started adding support for the small code
>>>>>         model.
>>>>>
>>>>>         Cheers,
>>>>>         Rafael
>>>>>         _______________________________________________
>>>>>         LLVM Developers mailing list
>>>>>         llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>
>>>>>         http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>
>>>>>
>>>>
>>>>     _______________________________________________
>>>>     LLVM Developers mailing list
>>>>     llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>
>>>>     http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>     _______________________________________________
>>>     LLVM Developers mailing list
>>>     llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>
>>>     http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20160215/5b328d75/attachment.html>