On 2016-06-08 13:35, Per Jessen wrote:
Carlos E. R. wrote:
I would run apache single-threaded with strace, but I can't on a production server :-)
You can attach to a PID of an already running process. strace can attach to children automatically, but I don't know if you can do that with PID.
Yes, but I can't tell which apache thread is going to run my request. Hmm, I guess I could strace all of them ....
Yes, that is what I meant. -f Trace child processes as they are created by currently traced processes as a result of the fork(2), vfork(2) and clone(2) system calls. Note that -p PID -f will attach all threads of process PID if it is multi-threaded, not only thread with thread_id = PID. -ff If the -o filename option is in effect, each processes trace is written to filename.pid where pid is the numeric process id of each process. This is incompatible with -c, since no per-process counts are kept. -b syscall If specified syscall is reached, detach from traced process. Currently, only execve syscall is supported. This option is useful if you want to trace multi-threaded process and therefore require -f, but don't want to trace its (potentially very complex) children. -- Cheers / Saludos, Carlos E. R. (from 13.1 x86_64 "Bottle" at Telcontar)