Em Tue, Mar 31, 2015 at 05:04:18PM +0900, Masami Hiramatsu escreveu:
> (2015/03/31 4:48), Arnaldo Carvalho de Melo wrote:
> > No, I can't, I'd say we should support that, i.e. inserting multiple
> > probes per command line, for different DSOs, etc. I.e. the above would
> > be equivalent to these two calls:
> > [root@ssdandy acme]# perf probe -a icmp_rcv
> > Added new event:
> > probe:icmp_rcv (on icmp_rcv)
> > You can now use it in all perf tools, such as:
> > perf record -e probe:icmp_rcv -aR sleep 1
> > [root@ssdandy acme]# perf probe -x ./ex -a main
> > Added new event:
> > probe_ex:main (on main in /home/acme/ex)
> > You can now use it in all perf tools, such as:
> > perf record -e probe_ex:main -aR sleep 1
> > [root@ssdandy acme]#
> OK, finally we should support that.
> > But it isn't like that, so, yes, what you report is a bug, both for your
> > expectation (that I think is that it should put a uprobes with both your
> > examples) and for mine (that it would add the first to the kernel, and
> > the second to the selected DSO via -x).
> Yes, both are bugs. I'll fix that.
> BTW, let me check that the below behaviors are OK for you.
> perf probe -x BIN -a XXX
> -> setup XXX on BIN
Ok
> perf probe -a XXX -x BIN
> -> setup XXX on BIN
> perf probe -a XXX -x BIN -a YYY
> -> setup XXX on kernel and YYY on BIN
The two above are inconsistent, I think, first one, for me, doesn't make
sense, i.e. it says: Add XXX to the selected DSO, which, as none was
specified at that point, should be the kernel, right?
I.e. if we do:
> perf probe -a XXX
Without that extra -x that is coming _after_ the command to add a probe
to XXX (-a XXX), what is that the tool should do (does from day 1, when
'probe' was first introduced in tools/perf/):
Add a probe to XXX _in the kernel_, i.e. not specifying a DSO means: its
for the kernel.
So, for me:
> perf probe -a XXX -x BIN
> -> setup XXX on BIN
Is invalid (or inocuous if what one wants is to add a probe for XXX on
the BIN dso), because it doesn't make sense _if you want to support
adding multiple probes for different DSOs on the same command line_,
because it would mean:
Add a probe to XXX _in the kernel_, then select BIN as the DSO for
which probes will be then specified, but in this example, none are
specified after that "-x BIN", so, I think that:
perf probe -a XXX -x BIN
and:
perf probe -a XXX
Mean the same thing, i.e. add a probe for XXX in the kernel.
> perf probe -x BIN -a XXX -x BIN2 -a YYY
> -> setup XXX on BIN and YYY on BIN2
Ok.
Also, more generically, I think that:
perf probe -a AAA -a BBB -a CCC -a DDD -x /lib64/libc-2.17.so -a malloc -a free
\
-x /usr/lib64/libthread_db-1.0.so -a td_lookup -a td_thr_event_enable
Should add kprobes for AAA, BBB, CCC and DDD in the kernel, uprobes for
malloc and free on libc and uprobes for td_lookup and
td_thr_event_enable on libthread_db.
Making it even more compact would be a bonus:
perf probe -a AAA,BBB,CCC,DDD -x /lib64/libc-2.17.so -a malloc,free \
-x /usr/lib64/libthread_db-1.0.so -a td_lookup,td_thr_event_enable
:-)
- Arnaldo
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