Hello Kapil,
I have implemented a static profiler for LLVM as a google summer of
code project in 2009. I wrote it for the 2.4 branch, but the
implementation never made into the tree. I have recently ported it to
LLVM 2.8, but I haven't tested it. You can take a look at the code
from: http://homepages.dcc.ufmg.br/~rimsa/tools/stprof-llvm.patch
The implementation is based on Wu's [1994] paper and provides a
branch predictor that calculates probabilities. The implementation
also covers an intraprocedural and interprocedural frequency
calculator for edges and functions.
Reference:
Youfeng Wu and James R. Larus. Static branch frequency and program
profile analysis. In MICRO 27: Proceedings of the 27th annual
international symposium on Microarchitecture. IEEE, 1994.
Regards,
Andrei
On Tue, Nov 2, 2010 at 10:46 AM, Andrew Lenharth <andrewl at lenharth.org>
wrote:> On Tue, Nov 2, 2010 at 12:28 AM, kapil anand <kapilanand2 at
gmail.com> wrote:
>> Hi all,
>>
>> Does LLVM infrastructure contain implementation of any static profiling
>> algorithm apart from "Spill-Weight" calculation present in
Live Intervals
>> class? The future work page does suggest implementation of some
"static
>> profiling" algorithms to make an educated guesses about the
relative
>> execution frequencies of various parts of the code.
>
> If you look at old releases, there was a profiling library and
> transforms, including infrastructure to do any of the profiling with
> random sampling. Those were unmaintained and removed not that long
> ago. What you could profile was somewhat limited.
>
> Andrew
>
>
>> Thanks
>>
>> --Kapil
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>
>>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
Thanks Andrei! I haven't read the paper. I would see whether this fulfills my requirements or whether I need to make any changes. --Kapil On Tue, Nov 2, 2010 at 12:43 PM, Andrei Alvares <logytech at gmail.com> wrote:> Hello Kapil, > > I have implemented a static profiler for LLVM as a google summer of > code project in 2009. I wrote it for the 2.4 branch, but the > implementation never made into the tree. I have recently ported it to > LLVM 2.8, but I haven't tested it. You can take a look at the code > from: http://homepages.dcc.ufmg.br/~rimsa/tools/stprof-llvm.patch<http://homepages.dcc.ufmg.br/%7Erimsa/tools/stprof-llvm.patch> > > The implementation is based on Wu's [1994] paper and provides a > branch predictor that calculates probabilities. The implementation > also covers an intraprocedural and interprocedural frequency > calculator for edges and functions. > > Reference: > Youfeng Wu and James R. Larus. Static branch frequency and program > profile analysis. In MICRO 27: Proceedings of the 27th annual > international symposium on Microarchitecture. IEEE, 1994. > > Regards, > Andrei > > On Tue, Nov 2, 2010 at 10:46 AM, Andrew Lenharth <andrewl at lenharth.org> > wrote: > > On Tue, Nov 2, 2010 at 12:28 AM, kapil anand <kapilanand2 at gmail.com> > wrote: > >> Hi all, > >> > >> Does LLVM infrastructure contain implementation of any static profiling > >> algorithm apart from "Spill-Weight" calculation present in Live > Intervals > >> class? The future work page does suggest implementation of some "static > >> profiling" algorithms to make an educated guesses about the relative > >> execution frequencies of various parts of the code. > > > > If you look at old releases, there was a profiling library and > > transforms, including infrastructure to do any of the profiling with > > random sampling. Those were unmaintained and removed not that long > > ago. What you could profile was somewhat limited. > > > > Andrew > > > > > >> Thanks > >> > >> --Kapil > >> > >> _______________________________________________ > >> LLVM Developers mailing list > >> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > >> > >> > > > > _______________________________________________ > > LLVM Developers mailing list > > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20101102/e3ebac9e/attachment.html>
My god! I would love a branch predictor! It would simplify many aspects of my register allocator. Second, I am surprised it did not make it into the tree. Since more is being done with register allocation as a while "RegAllocBasic" was just put in, I hope this is looked at again. Do you have a working svn copy? Also, could you send me a copy/link to that '94 paper off the list please? -Thanks -Jeff Kunkel On Tue, Nov 2, 2010 at 6:57 PM, kapil anand <kapilanand2 at gmail.com> wrote:> Thanks Andrei! > > I haven't read the paper. I would see whether this fulfills my requirements > or whether I need to make any changes. > > --Kapil > > > On Tue, Nov 2, 2010 at 12:43 PM, Andrei Alvares <logytech at gmail.com>wrote: > >> Hello Kapil, >> >> I have implemented a static profiler for LLVM as a google summer of >> code project in 2009. I wrote it for the 2.4 branch, but the >> implementation never made into the tree. I have recently ported it to >> LLVM 2.8, but I haven't tested it. You can take a look at the code >> from: http://homepages.dcc.ufmg.br/~rimsa/tools/stprof-llvm.patch<http://homepages.dcc.ufmg.br/%7Erimsa/tools/stprof-llvm.patch> >> >> The implementation is based on Wu's [1994] paper and provides a >> branch predictor that calculates probabilities. The implementation >> also covers an intraprocedural and interprocedural frequency >> calculator for edges and functions. >> >> Reference: >> Youfeng Wu and James R. Larus. Static branch frequency and program >> profile analysis. In MICRO 27: Proceedings of the 27th annual >> international symposium on Microarchitecture. IEEE, 1994. >> >> Regards, >> Andrei >> >> On Tue, Nov 2, 2010 at 10:46 AM, Andrew Lenharth <andrewl at lenharth.org> >> wrote: >> > On Tue, Nov 2, 2010 at 12:28 AM, kapil anand <kapilanand2 at gmail.com> >> wrote: >> >> Hi all, >> >> >> >> Does LLVM infrastructure contain implementation of any static profiling >> >> algorithm apart from "Spill-Weight" calculation present in Live >> Intervals >> >> class? The future work page does suggest implementation of some "static >> >> profiling" algorithms to make an educated guesses about the relative >> >> execution frequencies of various parts of the code. >> > >> > If you look at old releases, there was a profiling library and >> > transforms, including infrastructure to do any of the profiling with >> > random sampling. Those were unmaintained and removed not that long >> > ago. What you could profile was somewhat limited. >> > >> > Andrew >> > >> > >> >> Thanks >> >> >> >> --Kapil >> >> >> >> _______________________________________________ >> >> LLVM Developers mailing list >> >> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >> >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >> >> >> >> >> > >> > _______________________________________________ >> > LLVM Developers mailing list >> > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >> > >> > > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20101102/478ce0ab/attachment.html>