similar to: About Clang llvm PGO

Hi Diego, thanks for clarifying the difference between the two formats. I have noticed the new note in the "Sample Profile Format" section of the Clang guide clarifying that it is different from the coverage format. So, my further question is... Am I right in understanding that both formats can be used for PGO purposes then? I have tried the following, as in the Clang user guide: $

Hi, all Recently I'm trying to use LLVM PGO and autoFDO. However I have some problems in the process. LLVM source code is updated on April 9th. Operating system is SUSE x86_64 1. Problems in instrumentation based PGO: clang -O2 -fprofile-instr-generate test.c -o a.out ./a.out (then default.profraw is generated) clang -O2 -fprofile-instr-use=default.profraw test.c -o a.out

On Fri, May 22, 2015 at 11:16 AM, Dario Domizioli <dario.domizioli at gmail.com> wrote: > Hi all, > > I am a bit confused about the documentation of the format of the profile > data file. > > The Clang user guide here describes it as an ASCII text file: > http://clang.llvm.org/docs/UsersManual.html#sample-profile-format > > Whereas the posts above and the

The PGO was my first guess but I can get a lot of information. At first, I follow the explanation at http://clang.llvm.org/docs/UsersManual.html#profiling-with-instrumentation but instead of llvm-profdata merge, I used llvm-profdata show *.profraw. Sadly, the information I get is the total number of function, the maximum function count and the maximum internal block count. Do you know if you

On Tue, May 24, 2016 at 3:41 PM, Vedant Kumar <vsk at apple.com> wrote: > > > On May 23, 2016, at 8:56 PM, Xinliang David Li <davidxl at google.com> > wrote: > > > > On Mon, May 23, 2016 at 8:23 PM, Sean Silva <chisophugis at gmail.com> > wrote: > > Jake and I have been integrating IRPGO on PS4, and we've identified 3 > remaining work

On Fri, Mar 4, 2016 at 11:28 AM, Tilmann Scheller <tilmann at osg.samsung.com> wrote: > Hi Sedat, > > On 03/03/2016 08:09 AM, Sedat Dilek via llvm-dev wrote: >> >> It might be that a CLANG generated with LTO/PGO speeds up the build. >> Can you confirm this? > > Yes, a Clang host compiler built with LTO or PGO is generally faster than an > -O3 build. >

> On May 23, 2016, at 8:56 PM, Xinliang David Li <davidxl at google.com> wrote: > > On Mon, May 23, 2016 at 8:23 PM, Sean Silva <chisophugis at gmail.com> wrote: > Jake and I have been integrating IRPGO on PS4, and we've identified 3 remaining work items. > > Sean, thanks for the write up. It matches very well with what we think as well. + 1 > - Driver

> On May 24, 2016, at 5:21 PM, Sean Silva <chisophugis at gmail.com> wrote: > > > > On Tue, May 24, 2016 at 3:41 PM, Vedant Kumar <vsk at apple.com <mailto:vsk at apple.com>> wrote: > > > On May 23, 2016, at 8:56 PM, Xinliang David Li <davidxl at google.com <mailto:davidxl at google.com>> wrote: > > > > On Mon, May 23, 2016 at

It sounds to me we are likely to converge on the following: 1) Making IR/llvm based PGO the default; 2) Enhance -fcoverage-mapping such that it automatically turns on FE based instrumentation 3) if -fcoverage-mapping is used together with -fprofile-instr-generate, -fcoverage-mapping serves as a switch to turn on FE based instrumetnation All the above are transparent to users. The following are

Hi all, I am a bit confused about the documentation of the format of the profile data file. The Clang user guide here describes it as an ASCII text file: http://clang.llvm.org/docs/UsersManual.html#sample-profile-format Whereas the posts above and the referenced link describe it as a stream of bytes containing LEB128s: http://www.llvm.org/docs/CoverageMappingFormat.html >From experimenting

Hi everybody, I'm trying to get loop hotness data across a suite (e.g. the llvm test-suite). Ideally, this would be a list that for each loop would list how many times it was entered and what was its iteration count (at least the latter). The closest thing I could come up with is: - clang -fprofile-instr-generate (without opts) to get a .profraw - Get the .profdata - Give that back to clang

Hey, I am trying to use the BlockFrequencyInfoWrapperPass to obtain hotness information in my LLVM pass. Attached is a minimal example of code which creates a SIGSEGV. The pass calls AU.addRequired<BlockFrequencyInfoWrapperPass>(); in getAnalysisUsage(..). The problem exists with changed and unchanged IR. The binary is instrumented like this: clang input.bc -fprofile-generate -o

On Mon, May 23, 2016 at 8:23 PM, Sean Silva <chisophugis at gmail.com> wrote: > Jake and I have been integrating IRPGO on PS4, and we've identified 3 > remaining work items. > Sean, thanks for the write up. It matches very well with what we think as well. > > > - Driver changes > > We'd like to make IRPGO the default on PS4. We also think that it would be

Hi! I am trying to get a combined coverage report from multiple executables. Looking at earlier discussions [1, 2], it looks like this is supposed to work. I am having some difficulty getting this to work as I would expect it to work, however. Following is a simple case to explain: ////////// shared.h #include <string> void Print1(const std::string& msg); void Print2(const

Jake and I have been integrating IRPGO on PS4, and we've identified 3 remaining work items. - Driver changes We'd like to make IRPGO the default on PS4. We also think that it would be beneficial to make IRPGO the default PGO on all platforms (coverage would continue to use FE instr as it does currently, of course). In previous conversations (e.g. http://reviews.llvm.org/D15829) it has

Hello David, thanks for detailed response! Do you have any tests that you use to measure the PGO effectiveness? I have tested clang version 6.0 with the same sample that Jie Chen used in 2016 and actually both frontend-based PGO and IR-based make code run slower, see the average time: clang++ -O3: 3.15 sec  clang++ -O3 and -fprofile-instr-use: 3.160 sec clang++ -O3 and -fprofile-use: 3.180 sec

Hi all! It seems I came across on issue with coverage mapping (http://www.llvm.org/docs/CoverageMappingFormat.html) check on: llvm revision: r228136 clang Last Changed Rev: 228121 build: Debug+Asserts OS: ubuntu 14.04 Here is simple snippets test1.c: NOT OK ================== #include <stdio.h> static int foo() { return 42; } int main() { return 0; } ================== cp src/test1.c

Hi, I have a question regarding PGO. I collected profile data with the instrumentation build (-fprofile-instr-generate) and provided for PGO optimization in the second build (with -fprofile-instr-use=xxx.profdata). This works fine. Then I tried to provide the profile data to opt using the option -pgo-instr-use, but this causes an error with the message: "Not an IR level instrumentation

David, could you please clarify on which code did you gain 10% improvement? I have run numerous tests with and w/o this option and it looks like it has no effect on performance (I am talking of the old 2016 sample to be concrete). Maybe we could investigate it together? Just tell me where to start? On 02/07/2018 02:11 AM, Xinliang David Li wrote: > Victor, thanks for the experiment. > >

Hi all, I'd liked to get your thoughts on possibly adding a generic key-value store to the profile data formats for 'metadata'. Some potential uses cases: *I. Profile Features* The most basic use could be as a central repository for internal bits of housekeeping information about the profile data. For example, to differentiate between FE and IR instrumentation: