Profile displays only filenames (not functions/lines) on OSX about pprof

[Timmmm]

After installing llvm-symbolizer I managed to get this to work with a toy program:

$ brew install gperftools
$ rm /usr/local/bin/pprof
$ go get pprof                              # And add ~/go/bin to PATH
$ brew install llvm
$ ln -s /usr/local/opt/llvm/bin/llvm-symbolizer /usr/local/bin/llvm-symbolizer

$ mkdir tmp
$ cd tmp
$ echo "see example below" > main.cpp
$ clang++ -fno-pie -lprofiler -g -O0 main.cpp -o main
$ CPUPROFILE=prof.out ./main
$ pprof -weblist ".*" prof.out

This produces a nice output. -fno-pie is definitely necessary, otherwise it doesn't work.

However when I try it on my actual project I only get this output:

_mh_execute_header
??

Total: 0 200ms (flat, cum) 0.47%

I am building the project using QBS, and it seems that pprof thinks the executable is in /var/folders/hc/__somerandomstuff/T/mygreat-abe32b32 rather than its actual name mygreat_project. I don't know much about how QBS works but I guess it is building it in that temporary directory and then moving the result. Anyone have any idea what could be going on here?

Example profileable code

I used this from rosetta code:

 #include <cstdlib>
 #include <iostream>
 #include <sstream>
 #include <iomanip>
 #include <list>
  
 bool k_prime(unsigned n, unsigned k) {
     unsigned f = 0;
     for (unsigned p = 2; f < k && p * p <= n; p++)
         while (0 == n % p) { n /= p; f++; }
     return f + (n > 1 ? 1 : 0) == k;
 }
  
 std::list<unsigned> primes(unsigned k, unsigned n)  {
     std::list<unsigned> list;
     for (unsigned i = 2;list.size() < n;i++)
         if (k_prime(i, k)) list.push_back(i);
     return list;
 }
  
 int main(const int argc, const char* argv[]) {
     using namespace std;
     for (unsigned k = 1; k <= 20; k++) {
         ostringstream os("");
         const list<unsigned> l = primes(k, 10);
         for (list<unsigned>::const_iterator i = l.begin(); i != l.end(); i++)
             os << setw(4) << *i;
         cout << "k = " << k << ':' << os.str() << endl;
     }
  
 	return EXIT_SUCCESS;
 }

[rsc]

pprof translates addresses to line information using either GNU addr2line or LLVM llvm-symbolizer. I see you are on a Mac, which by default doesn't have either one. You need to find a way to install one or the other (probably llvm-symbolizer).

[qris]

Hi @rsc, thanks for the reply :) It's unfortunate that we depend on llvm-symbolizer which is not shipped on OSX and not readily available in Homebrew either. Do you know where I'm supposed to get it from? Do I have to build LLVM from source? Is it possible to use atos which does ship with OSX instead?

[tamird]

FWIW, llvm-symbolizer is available on brew, via the llvm formula. It is not necessary to build from source.

$ brew install llvm
...
$ (brew --prefix llvm)/bin/llvm-symbolizer
-r-xr-xr-x  1 tamird  admin   2.8M Mar  7 15:44 /usr/local/opt/llvm/bin/llvm-symbolizer
$

[rauls5382]

It should be possible to add atos support. I'll give that a stab

[qris]

Thanks both! I hadn't even thought to look for an LLVM package in Homebrew. I now have llvm-symbolizer installed, but I'm afraid I'm still not getting symbols resolved (apart from a few that look like OpenSSL libraries):

$ /usr/local/bin/pprof --text  ./_test /tmp/prof.out
Using local file ./_test.
Using local file /tmp/prof.out.
Total: 346 samples
      97  28.0%  28.0%       97  28.0% 0x00007fff8b94f362
      61  17.6%  45.7%       61  17.6% 0x00007fff8b94f2a2
      39  11.3%  56.9%       39  11.3% 0x00007fff8b94ef12
      27   7.8%  64.7%       27   7.8% 0x00007fff8b94d532
...
       0   0.0% 100.0%        1   0.3% 0x5c28d1c3ffffffff
       0   0.0% 100.0%        1   0.3% _EVP_DigestInit_ex
       0   0.0% 100.0%        1   0.3% _HMAC
       0   0.0% 100.0%        1   0.3% _HMAC_Init_ex
       0   0.0% 100.0%      315  91.0% __mh_execute_header

Any ideas for what else I could try?

[tamird]

PATH=$PATH:$(brew --prefix llvm)/bin/llvm-symbolizer /usr/local/bin/pprof --text ./_test /tmp/prof.out?

[qris]

@tamird thanks for the suggestion, but I'm afraid that doesn't help. I have llvm-symbolizer on my PATH anyway, so adding it again makes no difference.

[LukeXuan]

Hi, is there anymore progress? I'm still experiencing the same problem now(gperftools and standalone pprof)

[LukeXuan]

It seems that using -Wl,-no-pie compiler option fixes for the executable itself, but the system libraries are not fixed still.

[oceanusxiv]

I wish to report that I have this issue as well. @LukeXuan can you expand further on what you meant by the compiler option? I tried it in my CMakeslist.txt, and it didn't work for me. Further I couldn't even find that compiler option anywhere.

I am currently on MacOS 10.12, using GCC/G++ 7 (I wanted OpenMP), standalone pprof, and I installed binutils for addr2line. Note that binutils from homebrew named its exec gaddr2line, so I symlinked it to addr2line in /usr/local/bin. Which is how I can call it from terminal.

I can call addr2line from terminal, and a cursory look in the Go code seems like there is provision for pprof to look for addr2line from the current $PATH. I did not have the necessary time to figure out if Go was actually able to find addr2line or not, but I don't see why not.

[LukeXuan]

Hi, firstly I'm using llvm toolchain from homebrew(I just made sure that llvm-symbolizer is in the PATH). The compile command is like

clang++ -std=c++1z -Og -g3 -lprofiler -Wl,-no_pie source.cpp exec

Then nearly everything works fine for me.

[iamzhout]

I also get the same problem, when using pprof to show profile information, I just get below result:

$pprof --text ./test cpu-test.pprof
File: test
Type: cpu
Showing nodes accounting for 23.31s, 100% of 23.31s total
      flat  flat%   sum%        cum   cum%
    23.31s   100%   100%     23.31s   100%  [test]

while using go tool pprof, I can get detailed profile info, like below:

File: test
Type: inuse_space
Entering interactive mode (type "help" for commands, "o" for options)
(pprof) top
Showing nodes accounting for 627.26MB, 97.76% of 641.66MB total
Dropped 68 nodes (cum <= 3.21MB)
Showing top 10 nodes out of 47
      flat  flat%   sum%        cum   cum%
  223.52MB 34.83% 34.83%   223.52MB 34.83%  runtime.stackfree /home/test/bin/go/src/runtime/stack.go
  131.03MB 20.42% 55.25%   131.03MB 20.42%  runtime.mapassign /home/test/bin/go/src/runtime/hashmap.go
  107.52MB 16.76% 72.01%   107.52MB 16.76%  runtime.mallocinit /home/test/bin/go/src/runtime/malloc.go

[Timmmm]

Aha solved it! The problem was that I turned QBS's modules.cpp.positionIndependentCode option off but that doesn't add -fno-pie. I guess maybe it just sets it to 'auto' rather than forces it to off? Anyway with these options it finally works:

modules.cpp.linkerFlags:-lprofiler modules.cpp.driverFlags:-fno-pie modules.cpp.positionIndependentCode:false

[aalexand]

This should be fixed now with the recent improvements of handling binaries on OSX. Please file specific issues if still not working.