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Re: Top syscalls


Frank Ch. Eigler wrote:

I expect that when the system call tapset is finally constructed,
strings such as the plain system call names will be made available in
the new probe point aliases.  Is anyone now working on this?



Yes, system call tap set should export plain name. Kevin is working on it.

Yeah, no wonder this, repeated 20 times, is running out of the
MAXACTION quota, which is around 1000 statements. I hope we can think
of a way of expressing "top N" type queries using statistics objects,
or a sorting primitive, or something.



A built in assoc array sorting function would be great.


Be aware that this processing loop in fact does/should (bug #1275)
lock the syscall_count array for the duration of the iteration.  That
that means that concurent processes on other CPUs trying to perform
syscalls will be held in a spinlock.  So the MAXACTION limit performs
a useful function even in this case.




[...]
probe kernel.function("sys_*") {
if (pid() != get_daemon_pid())
accumulate ()
}



Did you find that this filtering was necessary? Was stpd showing up a lot? I thought it had learned to batch its kernel-to-user message passing, so as to produce a smaller footprint.



Actually, we don't need to do that filtering.



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