similar to: [LLVMdev] [Help] LLVM Runtime optimization and PGO reoptimization

Hello everybody, I would like to know more about runtime & idle time reoptimizer mentioned in the powerpoint presentations about LLVM. Which tool in the LLVM toolchain is responsible for this? Where I can find more details on how reoptimizer is implemented? If someone can let me know any doc or specific source code file to look at, it would be helpful. I have also seen a similar post by

It means using PGO with -O2 and above (including -O3). David On Sun, Jan 28, 2018 at 6:48 PM, Victor Leschuk via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Hello all, > > clang-related PGO documentation recommends using PGO with -O2 (for > example: > https://clang.llvm.org/docs/UsersManual.html#profile-guided-optimization). > The question is: is there any reason why

Maybe we should update the documentation to state this directly? Currently its a little bit confusing. On 01/29/2018 05:51 AM, Xinliang David Li wrote: > It means using PGO with -O2 and above (including -O3). > > David > > On Sun, Jan 28, 2018 at 6:48 PM, Victor Leschuk via llvm-dev > <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote: > >

Hello all, clang-related PGO documentation recommends using PGO with -O2 (for example: https://clang.llvm.org/docs/UsersManual.html#profile-guided-optimization). The question is: is there any reason why exactly -O2 is used in examples? Are there any factors which can cause problems when using PGO with -O3? Thanks in advance for your advice! -- Best Regards, Victor Leschuk | Software Engineer

Hi All, I've listed the current topics of interest below, along with some notes on each. We only have 30 minutes so we'll barely scratch the surface of these during the BoF itself. My main aims are for you to meet each other, identify potential areas of collaboration, identify things that I can do to unblock you, and get the ball rolling on some conversations that we can continue on the

On Sun, Feb 4, 2018 at 9:59 PM, Victor Leschuk <vleschuk at accesssoftek.com> wrote: > Hello David! > > I have recently started acquaintance with PGO in LLVM/clang and found > your e-mail thread: > http://lists.llvm.org/pipermail/llvm-dev/2016-May/099395.html . Here you > posted a nice list of optimizations that use profiling and of those > which could be using but

Victor, thanks for the experiment. My suspicion is it is due to the remaining issues with block layout -- especially with loop rotation (with PGO). Another problem is that tail dup is not happening after loop rotation which can limit the effectiveness of loop rotation. I tried the internal option -mllvm -force-precise-rotation-cost and there is about 10% speedup with -fprofile-use. This option

Dario Domizioli <dario.domizioli at gmail.com> writes: > 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

Victor, please file a bug tracking the issue. We can put relevant information there including test cases used in the experiment etc. thanks, David On Wed, Feb 7, 2018 at 2:15 PM, Victor Leschuk <vleschuk at accesssoftek.com> wrote: > 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

Hello, I'm working on Android kernel profile-guided optimization to figure out whether pgo can improve the performance of Android kernel. I have tried to added '-fprofile-generate' option to build Android kernel(msm-4.19). But error occurs during building: "undefined reference to '__llvm_profile_instrument_target'". I have tried to add

Hello David and all involved =) On 02/05/2018 09:38 AM, Xinliang David Li wrote: > ThinLTO also works well with PGO. Could you please let me know if there are any problems which prevent using PGO with FullLTO? Thanks in advance! -- Best Regards, Victor Leschuk | Software Engineer | Access Softek

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 Thu, May 28, 2015 at 9:56 AM, Philip Reames <listmail at philipreames.com> wrote: > > > On 05/27/2015 11:13 AM, Duncan P. N. Exon Smith wrote: >>> >>> On 2015 May 27, at 07:42, Diego Novillo <dnovillo at google.com> wrote: >>> >>> On Tue, May 26, 2015 at 11:47 PM, Lee Hunt <leehu at exchange.microsoft.com> >>> wrote:

Hi David! Thanks again for your help! I was wondering if you could clarify one thing for me? I find mention of “hot arc” optimization (-fprofile-arcs) , but I’m unclear if this is the same thing. Does Clang PGO do block reordering? It does reordering, but does not do splitting/partitioning. I take this to mean that PGO does block reordering within the function? I don’t see that the clang

I was trying to build llvm + clang with cmake cache PGO.cmake and ninja stage2. I used the 4.0.0 final tag vfrom svn. This seems to work for me. I added libcxx, libcxxabi, llld etc. And now I get the following cmake error. -- Performing Test LIBCXX_SUPPORTS_STD_EQ_CXX11_FLAG -- Performing Test LIBCXX_SUPPORTS_STD_EQ_CXX11_FLAG - Failed CMake Error at projects/libcxx/CMakeLists.txt:396

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 David, Thanks for your reply. I find that I need to add some new types of profile data that are specific to JIT environment like Function Ordering. Function Ordering is similar to dynamic call graph which records the execution of functions at runtime along with the order in which they are called. Eg: Suppose they are 5 functions (F1..F5). F1 calls other functions in the order described

Hello - I'm an Engineer in Microsoft Office after looking into possible advantages of using PGO for our Android Applications. We at Microsoft have deep experience with Visual C++'s Profile Guided Optimization<https://msdn.microsoft.com/en-us/library/e7k32f4k.aspx> and often see 10% or more reduction in the size of application code loaded after using PGO for key scenarios (e.g.

On 05/27/2015 11:13 AM, Duncan P. N. Exon Smith wrote: >> On 2015 May 27, at 07:42, Diego Novillo <dnovillo at google.com> wrote: >> >> On Tue, May 26, 2015 at 11:47 PM, Lee Hunt <leehu at exchange.microsoft.com> wrote: >> >>> For example, from reading different pages on how Clang PGO, it’s unclear if >>> it does “block reordering” (i.e. moving

Yes, thanks David! For the intra-procedural Basic Block Reordering, do you have any data as to how much improvement that gives speed-wise for any perf tests you’ve measured? I’m thinking this may speed things up for things like application launch by a couple %. For perf intensive code (e.g. spreadsheet recalc), I would expect it would be more. From: Randy Chapman Sent: Wednesday, May 27, 2015