Actually, I am compiling a very simple c program test.c with gcc -g test.c -o test
but it is not affecting output. Is there any way by which I can check whether the binary image generates debug info or not? On Fri, Mar 24, 2017 at 3:26 PM, Michael Petlan <mpet...@redhat.com> wrote: > Please read my previous message once more: > > Hi, I think you need to rebuild the test with '-g' switch. > If the test binary does not have debuginfo, opreport cannot > resolve that. > > On Fri, 24 Mar 2017, dhara buch wrote: > >> Hi, >> Yes, when I try to execute 'opreport --symbols --debug-info' command >> after doing profiling for a .c file (let operf ./test), >> >> I am expecting 'test.c:line_no' in linear info field as you are getting >> 'exact_counts.c:13' in the following: >> >> samples % linenr info image name >> symbol name >> 10 66.6667 (no location information) no-vmlinux >> /no-vmlinux >> 2 13.3333 exact_counts.c:13 exact_counts >> main >> 1 6.6667 exact_counts.c:10 exact_counts >> f_65535x >> 1 6.6667 exact_counts.c:9 exact_counts >> f_997x >> 1 6.6667 (no location information) ld-2.17.so >> _dl_fini >> I tried to install debuginfo using >> #debuginfo-install kernel command. >> >> But when I execute 'opreport --symbols --debug-info', I get only (no >> location information) in all of my samples. >> >> What may be the reason? >> > > The reason is that OProfile cannot find debuginfo of your test app. > Probably because it does not contain any ;-) > > Recompile your test application with the '-g' gcc switch. > > > FURTHER INFO: > > If you are profiling an application installed from packages, you > need to have the corresponding debuginfo package. For example, > for profiling firefox, you need firefox-debuginfo (RHEL, Fedora, > CentOS) or (probably) firefox-dbg packages (Ubuntu). It's also > good to have the debuginfos of all the required libraries. > > On RHEL/CentOS/Fedora, you can install that easily by: > debuginfo-install <your_package> > > Cheers, > Michael > > > >> On Thu, Mar 23, 2017 at 8:08 PM, Michael Petlan <mpet...@redhat.com> >> wrote: >> On Thu, 23 Mar 2017, dhara buch wrote: >> Hello, >> I am doing profiling with command, >> >> operf ./test --events=BR_INST_RETIRED >> where test.c is a simple c language file. >> >> then, I am trying to collect information with command >> >> opreport --symbols --debug-info >> >> From the documents of Oprofile, I assume that the above >> command lists profiling result as per the symbols i.e. I can get result >> showing samples, linear info, image >> name and symbol name. >> >> As per my command I expect my file name (test.c) to be in the >> linear info and image name, but shows [no location information] in linear >> info. The filename does not >> get listed in image >> name also. >> >> What is lacking? >> >> >> Hi, I think you need to rebuild the test with '-g' switch. >> If the test binary does not have debuginfo, opreport cannot >> resolve that. >> >> Me trying with debuginfo: >> >> samples % linenr info image name >> symbol name >> 10 66.6667 (no location information) no-vmlinux >> /no-vmlinux >> 2 13.3333 exact_counts.c:13 exact_counts >> main >> 1 6.6667 exact_counts.c:10 exact_counts >> f_65535x >> 1 6.6667 exact_counts.c:9 exact_counts >> f_997x >> 1 6.6667 (no location information) ld-2.17.so >> _dl_fini >> >> And without: >> >> samples % linenr info image name >> symbol name >> 10 55.5556 (no location information) no-vmlinux >> /no-vmlinux >> 3 16.6667 (no location information) exact_counts >> f_65535x >> 2 11.1111 (no location information) exact_counts >> main >> 1 5.5556 (no location information) ld-2.17.so >> _dl_add_to_slotinfo >> 1 5.5556 (no location information) ld-2.17.so >> _dl_next_tls_modid >> 1 5.5556 (no location information) ld-2.17.so >> _dl_relocate_object >> >> Is this the problem you are asking about? >> >> >> I tried to set vmlinux with operf --vmlinux option also where >> vmlinux file in in /usr/lib/debug/lib/4*/vmlinux, still the above commands >> do not list test file >> entries. >> >> >> The "--vmlinux" option is there for enabling this for samples >> obtained in kernelspace. >> >> By default (assuming you have no kernel debuginfo available), >> operf marks all the samples taken in kernel (e.g. your program >> called a syscall and the sample was taken when the syscall was >> being executed or you profile systemwide) as "no-vmlinux". >> >> This is sufficient if you care about userspace only and not about >> the "time" spent in kernel. >> >> If you care about kernelspace, you need the '--vmlinux' option >> with correct path specified. >> >> >> What is lacking? >> >> Thank you, >> >> Dhara buch >> >> >> >> Has this helped? >> >> Cheers, >> Michael >> >> >> >>
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