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 >
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