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SubjectRe: [PATCH v2] perf trace: Fix missing handling of --call-graph dwarf
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On 01/12/2018 09:02 PM, Arnaldo Carvalho de Melo wrote:
> Em Fri, Jan 12, 2018 at 01:47:06PM -0300, Arnaldo Carvalho de Melo escreveu:
>> There is still room for improvement, I noticed overriding is not working
>> for the probe event, investigating it now.
>
> So, I had to fix this another way to get the possibility of overwriting
> the global options (--max-stack, --call-graph) in an specific tracepoint
> event:
>
> http://git.kernel.org/acme/c/08e26396c6f2
>
> replaced that HEAD.
>
> This cset may take some more minutes to show up, just pushed.
>

Sorry this does *not* work on my s390x.

I have cloned your perf/core tree and above commit is included.
Here is the command I tried:

[root@s8360047 perf]# ./perf trace -vv --no-syscalls --max-stack 4 --call-graph dwarf
-e probe_libc:inet_pton -- ping -6 -c 1 ::1
callchain: type DWARF
callchain: stack dump size 8192
------------------------------------------------------------
perf_event_attr:
type 2
size 112
config 0x45f
{ sample_period, sample_freq } 1
sample_type IP|TID|TIME|ADDR|CPU|PERIOD|RAW|DATA_SRC
disabled 1
inherit 1
mmap 1
comm 1
enable_on_exec 1
task 1
mmap_data 1
sample_id_all 1
exclude_guest 1
mmap2 1
comm_exec 1
{ wakeup_events, wakeup_watermark } 1
------------------------------------------------------------
sys_perf_event_open: pid 6735 cpu 0 group_fd -1 flags 0x8 = 3
sys_perf_event_open: pid 6735 cpu 1 group_fd -1 flags 0x8 = 4
mmap size 2101248B
perf event ring buffer mmapped per cpu
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.070 ms

--- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.070/0.070/0.070/0.000 ms
0.000 probe_libc:inet_pton:(3ffada42060))
[root@s8360047 perf]#

I do miss in sample_type bits for CALLCHAIN, STACK_USER and REG_USER
in the debug output of the perf_event_open() attribute printout.

When I invoke the command with
[root@s8360047 perf]# ./perf trace -vv --no-syscalls
-e probe_libc:inet_pton/call-graph=dwarf,max-stack=3/ -- ping -6 -c 1 ::1
callchain: type DWARF
callchain: stack dump size 8192
------------------------------------------------------------
perf_event_attr:
type 2
size 112
config 0x45f
{ sample_period, sample_freq } 1
sample_type IP|TID|TIME|CALLCHAIN|CPU|PERIOD|RAW|REGS_USER|STACK_USER
disabled 1
inherit 1
mmap 1
comm 1
enable_on_exec 1
task 1
sample_id_all 1
exclude_guest 1
exclude_callchain_user 1
mmap2 1
comm_exec 1
{ wakeup_events, wakeup_watermark } 1
sample_regs_user 0x3ffffffff
sample_stack_user 8192
sample_max_stack 3
------------------------------------------------------------
sys_perf_event_open: pid 6768 cpu 0 group_fd -1 flags 0x8 = 3
sys_perf_event_open: pid 6768 cpu 1 group_fd -1 flags 0x8 = 4
mmap size 528384B
perf event ring buffer mmapped per cpu
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.074 ms

--- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.074/0.074/0.074/0.000 ms
[... snip ....]

unwind: _start:ip = 0x2aa1e38457b (0x457b)
0.000 probe_libc:inet_pton:(3ff9b142060))
__GI___inet_pton (/usr/lib64/libc-2.26.so)
gaih_inet (inlined)
__GI_getaddrinfo (inlined)
main (/usr/bin/ping)
__libc_start_main (/usr/lib64/libc-2.26.so)
_start (/usr/bin/ping)
[root@s8360047 perf]#

I see the proper result as expected.

--
Thomas Richter, Dept 3303, IBM LTC Boeblingen Germany
--
Vorsitzende des Aufsichtsrats: Martina Koederitz
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294

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