Messages in this thread | | | Date | Mon, 23 Jun 2014 08:00:31 -0600 | From | David Ahern <> | Subject | Re: [PATCH v2 0/7] perf trace pagefaults |
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On 6/20/14, 9:24 AM, Arnaldo Carvalho de Melo wrote: > Right now it is too simple, but I was starting to work (when you jumped > right in with your work making me stop and go on testing/reviewing :) ) > on making it more generic so that we could defer pretty printing the > arguments from sys_enter to sys_exit, when, by then, we would already > have an association of a user level pointer in some specific thread to > its contents. > > This will allow us to to resolve the pathname pointer in things like > open() (i.e. not just after that, in the fd syscalls (write, etc)) and > as well any other pointer of interest. > > By librarizing 'builtin-probe.c', that now uses lots of global > variables, etc, we would be able to insert probes where we want them to > capture the contents of pointers, check if the probes are already in > place, use just the ones that we managed to insert (i.e. that were not > invalid because the places where we wanted them to be were changed > across kernel releases, etc). > > I.e. no need for actual tracepoints from day one, just wannabe > tracepoints using whatever probe inserting gizmo the kprobes_tracer used > by 'perf probe' now thinks its best to use. > > Combine that with using DWARF descriptions (that could be pre cached > into something like CTF (the DTrace kind of CTF) or similar) like pahole > does and we would mostly automatically do all this work of prettyfing > syscall parameters. > > </handwave>
That was so much handwaving you could keep cool at a World Cup game. :-)
David
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