similar to: [LLVMdev] Questions about LLVM PGO and autoFDO

I am looking for advice on a problem observed with -fprofile-sample-use for samples built with the AutoFDO tool I took the "hmmer" benchmark out of SPEC2006 It is initially compiled clnag++ -o hmmer -O3 -std=gnu89 -DSPEC_CPU -DNDEBUG -fno-strict-aliasing -w -g *.c This baseline binary runs in about 164.2 seconds as reported by "perf stat" We build a sample file from this

Hi all, Here I include an RFC for control flow sensitive AutoFDO (FS-AFDO). This is a joint work with David Li. Questions and feedback are welcome. Thanks, Rong ============= [RFC] Control Flow Sensitive AutoFDO (FS-AFDO) 1. Motivation AFDO profile is derived from PMU samples from running an earlier build binary. PMU samples are indexed by the IP addresses. An offline tool uses the debug

Ok, here is the patch again... I also included fixes for the bits that originally gave my mailer fits... Two votes for orange, so I went with orange... Doing diffs in .: --- ./lib/AsmParser/LLLexer.cpp.~1~ 2007-12-14 22:09:06.000000000 -0800 +++ ./lib/AsmParser/LLLexer.cpp 2007-12-15 13:02:47.000000000 -0800 @@ -54,7 +54,7 @@ static uint64_t HexIntToVal(const char * Result +=

Newer g++ compilers can emit: /Volumes/mrs5/net/llvm/llvm/llvm/lib/AsmParser/LLLexer.cpp: In member function 'int llvm::LLLexer::LexAt()': /Volumes/mrs5/net/llvm/llvm/llvm/lib/AsmParser/LLLexer.cpp:287: warning: suggest a space before ';' or explicit braces around empty body in 'for' statement /Volumes/mrs5/net/llvm/llvm/llvm/lib/AsmParser/LLLexer.cpp: In member

On Dec 15, 2007, at 2:13 AM, Duncan Sands wrote: > Hi, > >> - for (++CurPtr; isdigit(CurPtr[0]); ++CurPtr); >> + for (++CurPtr; isdigit(CurPtr[0]); ++CurPtr) ; > > personally I like > > for (++CurPtr; isdigit(CurPtr[0]); ++CurPtr) {} > > better since it is more explicit. I think the bikeshed should be orange: for (++CurPtr; isdigit(CurPtr[0]);

Hi, > - for (++CurPtr; isdigit(CurPtr[0]); ++CurPtr); > + for (++CurPtr; isdigit(CurPtr[0]); ++CurPtr) ; personally I like for (++CurPtr; isdigit(CurPtr[0]); ++CurPtr) {} better since it is more explicit. Ciao, Duncan.

With recent bug fixes and performance tunings, AutoFDO at llvm has reached a usable state. To evaluate performance, we used O3/-fprofile-use/-fprofile-sample-use respectively to optimize clang itself, and measure its speed. clang built with -fprofile-use is ~20% faster than clang built with O3 clang built with -fprofile-sample-use is ~10% faster than clang built with O3 AutoFDO can deliver 50%

On Fri, Aug 12, 2016 at 12:15 PM, Xinliang David Li via llvm-dev < llvm-dev at lists.llvm.org> wrote: > +dehao. > > There are two potential problems: > > 1) the branch gets eliminated in the binary that is being profiled, so > there is no profile data > This seems like a fundamental problem for PGO. Maybe it is also responsible for this bug:

Michael Spencer via llvm-dev <llvm-dev at lists.llvm.org> writes: > I've recently implemented profile guided section layout in llvm + lld using > the Call-Chain Clustering (C³) heuristic from > https://research.fb.com/wp-content/uploads/2017/01/cgo2017-hfsort-final1.pdf > . In the programs I've tested it on I've gotten from 0% to 5% performance > improvement over

Hello! (+cc Adam Nemet, since he presented on optimization remarks at LLVM Dev Mtg 2016) I have a large C++ program, which I am compiling using a sampling profile generated via perf and AutoFDO. I'd like to use this profile in order to show the hotness of each code path that is displayed in the new optimization remarks viewer tool ( https://www.youtube.com/watch?v=qq0q1hfzidg). It seems,

Hi Rong, This is a very interesting proposal. We've also observed profile quality degradation from CFG destructive pass like loop rotate, and I can see how this proposal would help improve quality of profile that drives later optimization passes in the pipeline. I have a few questions. * How does this affect today's AutoFDO? Specifically, can users upgrade compiler with FS-AutoFDO

Hi Djordje, On Wed, Sep 9, 2020 at 7:52 AM Djordje Todorovic <Djordje.Todorovic at syrmia.com> wrote: > Using entry-values ('callee' side of the feature) is not enough in any case. It is always connected to the call-site-param (function arguments but we call it call-site-params; 'caller' side of the feature) debug info. I believe that there are call-site-params that could

Am 28.08.2011 20:02, schrieb geovanisouza92 at gmail.com: > Hi, Jo! > > I'm trying create a new programming language, and I want that it have > Unicode support (support for read and manipulate rightly the source-code and > string literals). > > But, in addition, my programming language supports "string interpolation" > string, and in these interpolations, tiny

Hi all (No idea if I have the correct audience. Please CC more people as needed). I have an UBSan failure in BumpPtrAllocatorImpl.Allocate. The problem is that lld requests that we StringRef::copy an empty string. This passes a length of 0 to a BumpPtrAllocator. The BumpPtrAllocator happened to not have anything allocated yet so the CurPtr is nullptr, but given that we need 0 space we think

Hi All, Our team at Facebook is building a new context-sensitive Sample PGO as an alternative to the existing AutoFDO. We’d like to share our motivation, propose a new design, and reveal preliminary results on benchmarks. We will refer to the proposed design as CSSPGO in this RFC. The new CSSPGO leverages simultaneous LBR and stack sampling to construct a full context-sensitive profile. It

On Tue, Mar 22, 2016 at 5:30 PM, Pete Cooper <peter_cooper at apple.com> wrote: > Hi all > > (No idea if I have the correct audience. Please CC more people as needed). > > I have an UBSan failure in BumpPtrAllocatorImpl.Allocate. > > The problem is that lld requests that we StringRef::copy an empty string. > This passes a length of 0 to a BumpPtrAllocator. The

> On Mar 22, 2016, at 5:35 PM, David Blaikie <dblaikie at gmail.com> wrote: > > > > On Tue, Mar 22, 2016 at 5:30 PM, Pete Cooper <peter_cooper at apple.com <mailto:peter_cooper at apple.com>> wrote: > Hi all > > (No idea if I have the correct audience. Please CC more people as needed). > > I have an UBSan failure in

On Tue, Mar 22, 2016 at 5:30 PM, Pete Cooper via llvm-dev <llvm-dev at lists.llvm.org> wrote: > Hi all > > (No idea if I have the correct audience. Please CC more people as needed). > > I have an UBSan failure in BumpPtrAllocatorImpl.Allocate. > > The problem is that lld requests that we StringRef::copy an empty string. > This passes a length of 0 to a

See my answers inline. From: Xinliang David Li <davidxl at google.com> Date: Friday, August 7, 2020 at 7:57 PM To: Wenlei He <wenlei at fb.com> Cc: "llvm-dev at lists.llvm.org" <llvm-dev at lists.llvm.org>, Wei Mi <wmi at google.com>, Hongtao Yu <hoy at fb.com> Subject: Re: [RFC] Context-sensitive Sample PGO with Pseudo-Instrumentation On Fri, Aug 7,

Thanks for the thoughtful questions, David. See my answers inline. Thanks, Wenlei From: Xinliang David Li <davidxl at google.com> Date: Friday, August 7, 2020 at 1:24 PM To: Wenlei He <wenlei at fb.com> Cc: "llvm-dev at lists.llvm.org" <llvm-dev at lists.llvm.org>, Wei Mi <wmi at google.com>, Hongtao Yu <hoy at fb.com> Subject: Re: [RFC] Context-sensitive