Thanks Sasha, Yonghong. Looks like both php and python use semaphores. Is it fundamentally not possible to enable this systemwide or is it a feature which hasn't been implemented? Maybe we get pids of the process as they hit another probe and then get the semaphore addresses and enable them? Or is there a way to start the processes with the semaphore enabled -- a elf indicator or something? Just thinking out loud.
Thanks, Kiran On Mon, Jan 15, 2018 at 10:30 PM, Sasha Goldshtein <[email protected]> wrote: > Please note that some USDT probes have an associated "semaphore", > which is really just a memory location that the probed code checks > before actually invoking the probe. You cannot enable USDT probes that > have a semaphore system-wide, without a process ID, because the > semaphore location has to be poked in each target process. > > To see if your probes have an associated semaphore, just run tplist with > -v -v and it will print out the semaphore address for each probe. If it's > 0, you're good to do system-wide tracing. > > Sasha > > > On Tue, Jan 16, 2018 at 8:08 AM Y Song via iovisor-dev > <[email protected]> wrote: >> >> Kiran, >> >> Yes, tracing through USDT without PID should work. >> You can just remove "-p" parameter and give a try. >> >> Please try latest bcc as it fixed a few bugs. >> Let us know if you hit any issues. >> >> Yonghong >> >> >> On Mon, Jan 15, 2018 at 5:11 PM, Kiran T via iovisor-dev >> <[email protected]> wrote: >> > I meant to say >> > >> > Can one request to monitor binaries -- like with >> > uprobes/uretprobes but with USDT? >> > >> > On Mon, Jan 15, 2018 at 5:09 PM, Kiran T <[email protected]> wrote: >> >> Hi >> >> All the examples on tracing processes with USDT require the pid of the >> >> traced program: >> >> >> >> https://github.com/iovisor/bcc/tree/master/examples/tracing >> >> >> >> Can one not request to monitor binaries -- like with >> >> uprobes/uretprobes but with USDT? >> >> >> >> I am trying to trace php scripts running on a webserver, and USDT >> >> would be ideal. But, I won't have the pid of the process that will be >> >> spawned by the webserver in advance. >> >> >> >> Thanks, >> >> Kiran >> > _______________________________________________ >> > iovisor-dev mailing list >> > [email protected] >> > https://lists.iovisor.org/mailman/listinfo/iovisor-dev >> _______________________________________________ >> iovisor-dev mailing list >> [email protected] >> https://lists.iovisor.org/mailman/listinfo/iovisor-dev _______________________________________________ iovisor-dev mailing list [email protected] https://lists.iovisor.org/mailman/listinfo/iovisor-dev
