Xinliang David Li
2013-Jun-12 23:26 UTC
[LLVMdev] RFC - Profile Guided Optimization in LLVM
> > After the basic profile-based transformations are working, I would like to > add new sources of profile. Mainly, I am thinking of implementing Auto > FDO. >For those who are not familiar with what autoFDO is -- Auto FDO is originally called Sample Based FDO. Its main author is Dehao Chen @google, and Robert Hundt is the one of the main pushers of technology in Google. The latest incarnation of this technology uses LBR events available on Nehalem and above. http://www.computer.org/csdl/trans/tc/2013/02/ttc2013020376-abs.html Cheers, David -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130612/bef348f4/attachment.html>
Apple folks are also gearing up to push on the PGO front. We are primarily interested in using instrumentation, rather than sampling, to collect profile info. However, I suspect the way profile ended up being used in the various optimization and codegen passes would be largely similar. There is also some interests in pursuing profile directed specialization. But that can wait. I think it makes sense for us to get together and discuss our plans to make sure there won't be duplication of efforts. Evan Sent from my iPad On Jun 12, 2013, at 4:26 PM, Xinliang David Li <xinliangli at gmail.com> wrote:> >> >> After the basic profile-based transformations are working, I would like to add new sources of profile. Mainly, I am thinking of implementing Auto FDO. > > For those who are not familiar with what autoFDO is -- Auto FDO is originally called Sample Based FDO. Its main author is Dehao Chen @google, and Robert Hundt is the one of the main pushers of technology in Google. The latest incarnation of this technology uses LBR events available on Nehalem and above. http://www.computer.org/csdl/trans/tc/2013/02/ttc2013020376-abs.html > > Cheers, > > David > _______________________________________________ > 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/20130615/7cb73213/attachment.html>
On 2013-06-15 14:18 , Evan Cheng wrote:> Apple folks are also gearing up to push on the PGO front. We are > primarily interested in using instrumentation, rather than sampling, > to collect profile info. However, I suspect the way profile ended up > being used in the various optimization and codegen passes would be > largely similar. >Excellent! We are initially interested in instrumentation, as well. This is where we draw most of our performance with GCC. Sampling is showing a lot of promise, however. And it really is not much different than instrumentation. Most of what changes is the source of profile data.> There is also some interests in pursuing profile directed > specialization. But that can wait. I think it makes sense for us to > get together and discuss our plans to make sure there won't be > duplication of efforts.Sure. My initial plan is fairly simple. Triage the existing instrumentation code and see what needs fixing. I'm starting this in the next week or so. What are your plans? Diego. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130617/df923727/attachment.html>