[LLVMdev] Very slow performance of lli on x86
j.prasanth.j at gmail.com
Sun Nov 15 01:55:53 CST 2009
Sorry i really forgot to mention one thing. I downloaded the X86 binaries of
llvm+clang and llvm-gcc from llvm download site. i hope that is not a debug
On Sun, Nov 15, 2009 at 1:22 PM, Prasanth J <j.prasanth.j at gmail.com> wrote:
> Hi all,
> LLVM is built without debug enabled. Also i am not forcing lli to use
> interpreter mode. so i dont think the reason is not because of debug build
> or interpreter mode.
> *step 1: *
> compiled the 3 files (generic_replica.c ,xacc.c and dacc.c) with clang-cc
> to llvm bytecode files using -emit-llvm-bc and (-O0/-O3) options
> *step 2:*
> bytecode obtained from step 1 (generic_replica.bc, xacc.bc and dacc.bc) is
> passed to opt tool using (-O0/-O3) options
> *step 3:*
> optimized bytecode obtained from step 2 (generic_replica.opt.bc,
> xacc.opt.bc and dacc.opt.c) is combinde to a single bytecode file
> (monolith.bc) using llvm-ld tool
> *step 4: *
> running monolith.bc for 10000 iterations using lli tool and measured the
> I also tried using llvm-gcc for emiting bytecode in step 1 but got almost
> the same output. As i have my entire setup in office i cant attach my
> makefile today. i will attach my entire setup tom once i get back to office.
> Also i will attach the configuration options i used for compiling LLVM. Let
> me know in case i am wrong anywhere.
> Thanks & Regards,
> Prasanth J
> On Sun, Nov 15, 2009 at 3:40 AM, Evan Cheng <evan.cheng at apple.com> wrote:
>> He is probably using the interpreter on a debug build.
>> On Nov 14, 2009, at 1:40 PM, Eric Christopher <echristo at apple.com> wrote:
>>>> for -O3 results refer attachment.
>>>> time clang (-O0)
>>>> llvm-gcc(-O0) gcc(-O0)
>>>> real 0m10.247s
>>>> 0m11.324s 0m10.963s
>>>> user 0m2.644s
>>>> 0m2.478s 0m2.263s
>>>> sys 0m5.949s
>>>> 0m6.000s 0m5.953s
>>>> i used clang-cc -O0 -emit-llvm-bc to emit llvm bytecode and then passed
>>>> it to opt tool and then linked all bytecode files to single bytecode using
>>>> llvm-ld, i used lli tool to run this single bytecode file and noticed the
>>>> following output
>>>> real 6m33.786s
>>>> user 5m12.612s
>>>> sys 1m1.205s
>>>> why is lli taking such a loooong time to execute this particular piece
>>>> of code.??
>>> Something's wrong on your machine or something. I did the same (but using
>>> llvm-gcc for the .ll files). Using a debug build of current ToT I got this:
>>> [ghostwheel:~/Desktop] echristo% time
>>> ~/builds/build-llvm-64bit/Debug/bin/lli foo.bc.bc
>>> 0.210u 0.010s 0:00.22 100.0% 0+0k 0+0io 0pf+0w
>>> That's a 64-bit build, but you'll notice the time difference. That said
>>> I'm guessing that there's something missing since it takes no time to
>>> execute. Step by step directions on what you did might help.
>>> LLVM Developers mailing list
>>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the LLVMdev