> > > > and commands like: > > perf record -a -e probe_libc:free --filter "common_pid == 1127" > > perf record -e probe_libc:free --filter "arg1 == 0xa" ls > > > > got me proper results. > > Btw., Srikar, if that's the primary UI today then we'll need to > make it a *lot* more user-friendly than the above usage > workflow. > > In particular this line: > > > echo "p:probe_libc/free /lib64/libc-2.13.so:0x7a4f0 %ax" > ./uprobe_events > > is not something a mere mortal will be able to figure out. Agree, perf probe is the primary interface to use uprobes. > > There needs to be perf probe integration, that allows intuitive > usage, such as: > > perf probe add libc:free Current usage is like perf probe -x <executable> -a <func1> -a <func2> So we could use perf probe -x /lib64/libc.so.6 free or perf probe -x /lib64/libc.so.6 -a free -a malloc -a strcpy The -x option helps perf to identify that its a user space based probing. This currently restricts that all probes defined per "perf probe" invocation to just one executable. This usage was suggested by Masami. Earlier we used perf probe free@/lib/libc.so.6 malloc@/lib/libc.so.6 The objection for this was that perf was already using @ to signify source file. Similarly : is already used for Relative line number. This also goes with perf probe -F -x /lib64/libc.so to list the available probes in libc. > > Using the perf symbols code it should first search a libc*so DSO > in the system, finding say /lib64/libc-2.15.so. The 'free' > symbol is readily available there: While I understand the ease of using a libc instead of the full path, I think it does have few issues. - Do we need to keep checking if the new files created in the system match the pattern and if they match the pattern, dynamically add the files? - Also the current model helps if the user wants to restrict his trace to particular executable where there are more that one executable with the same name. > > aldebaran:~> eu-readelf -s /lib64/libc-2.15.so | grep ' free$' > 7186: 00000039ff47f080 224 FUNC GLOBAL DEFAULT 12 free > > then the tool can automatically turn that symbol information > into the specific probe. > Given a function in an executable, we are > Will it all work with DSO randomization, prelinking and default > placement as well? Works with DSO randomization, I havent tried with prelinking. did you mean http://en.wikipedia.org/wiki/Placement_syntax#Default_placement when you said default placement? > > Users should not be expected to enter magic hexa numbers to get > a trivial usecase going ... yes, that why we dont allow perf probe -x /lib/libc.so.6 0x1234 > > this bit: > > > perf record -a -e probe_libc:free --filter "common_pid == 1127" > > perf record -e probe_libc:free --filter "arg1 == 0xa" ls > > looks good and intuitive and 'perf list' should list all the > available uprobes. Currently "perf probe -F -x /bin/zsh" lists all available functions in zsh. perf probe --list has been enhanced to show uprobes that are already registered. Similar to kprobes based probes, available user space probes are not part of "perf list". > > Thanks, > > Ingo > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>