perf report: Print al_addr when symbol is not found
For branch mode, if the symbol is not found, it prints
the address.
For example, 0x0000555eee0365a0 in below output.
Overhead Command Source Shared Object Source Symbol Target Symbol
17.55% div libc-2.27.so [.] __random [.] __random
6.11% div div [.] 0x0000555eee0365a0 [.] rand
6.10% div libc-2.27.so [.] rand [.] 0x0000555eee036769
5.80% div libc-2.27.so [.] __random_r [.] __random
5.72% div libc-2.27.so [.] __random [.] __random_r
5.62% div libc-2.27.so [.] __random_r [.] __random_r
5.38% div libc-2.27.so [.] __random [.] rand
4.56% div libc-2.27.so [.] __random [.] __random
4.49% div div [.] 0x0000555eee036779 [.] 0x0000555eee0365ff
4.25% div div [.] 0x0000555eee0365fa [.] 0x0000555eee036760
But it's not very easy to understand what the instructions
are in the binary. So this patch uses the al_addr instead.
With this patch, the output is
Overhead Command Source Shared Object Source Symbol Target Symbol
17.55% div libc-2.27.so [.] __random [.] __random
6.11% div div [.] 0x00000000000005a0 [.] rand
6.10% div libc-2.27.so [.] rand [.] 0x0000000000000769
5.80% div libc-2.27.so [.] __random_r [.] __random
5.72% div libc-2.27.so [.] __random [.] __random_r
5.62% div libc-2.27.so [.] __random_r [.] __random_r
5.38% div libc-2.27.so [.] __random [.] rand
4.56% div libc-2.27.so [.] __random [.] __random
4.49% div div [.] 0x0000000000000779 [.] 0x00000000000005ff
4.25% div div [.] 0x00000000000005fa [.] 0x0000000000000760
Now we can use objdump to dump the object starting from 0x5a0.
For example,
objdump -d --start-address 0x5a0 div
00000000000005a0 <rand@plt>:
5a0: ff 25 2a 0a 20 00 jmpq *0x200a2a(%rip) # 200fd0 <__cxa_finalize@plt+0x200a20>
5a6: 68 02 00 00 00 pushq $0x2
5ab: e9 c0 ff ff ff jmpq 570 <srand@plt-0x10>
...
Committer testing:
[root@seventh ~]# perf record -a -b sleep 1
[root@seventh ~]# perf report --header-only | grep cpudesc
# cpudesc : Intel(R) Core(TM) i5-7500 CPU @ 3.40GHz
[root@seventh ~]# perf evlist -v
cycles: size: 120, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|BRANCH_STACK, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1, branch_sample_type: ANY
[root@seventh ~]#
Before:
[root@seventh ~]# perf report --stdio --dso libsystemd-shared-241.so | head -20
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 2K of event 'cycles'
# Event count (approx.): 2240
#
# Overhead Command Source Shared Object Source Symbol Target Symbol Basic Block Cycles
# ........ ............... ........................ ...................... ...................... ..................
#
0.13% systemd-journal libc-2.29.so [.] cfree@GLIBC_2.2.5 [.] _int_free 1
0.09% systemd libsystemd-shared-241.so [.] 0x00007fe406465c82 [.] 0x00007fe406465d80 1
0.09% systemd libsystemd-shared-241.so [.] 0x00007fe406465ded [.] 0x00007fe406465c30 1
0.09% systemd libsystemd-shared-241.so [.] 0x00007fe406465e4e [.] 0x00007fe406465de0 1
0.09% systemd-journal systemd-journald [.] free@plt [.] cfree@GLIBC_2.2.5 1
0.09% systemd-journal libc-2.29.so [.] _int_free [.] _int_free 18
0.09% systemd-journal libc-2.29.so [.] _int_free [.] _int_free 2
0.04% systemd libsystemd-shared-241.so [.] bus_resolve@plt [.] bus_resolve 204
0.04% systemd libsystemd-shared-241.so [.] getpid_cached@plt [.] getpid_cached 7
[root@seventh ~]#
After:
[root@seventh ~]# perf report --stdio --dso libsystemd-shared-241.so | head -20
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 2K of event 'cycles'
# Event count (approx.): 2240
#
# Overhead Command Source Shared Object Source Symbol Target Symbol Basic Block Cycles
# ........ ............... ........................ ...................... ...................... ..................
#
0.13% systemd-journal libc-2.29.so [.] cfree@GLIBC_2.2.5 [.] _int_free 1
0.09% systemd libsystemd-shared-241.so [.] 0x00000000000f7c82 [.] 0x00000000000f7d80 1
0.09% systemd libsystemd-shared-241.so [.] 0x00000000000f7ded [.] 0x00000000000f7c30 1
0.09% systemd libsystemd-shared-241.so [.] 0x00000000000f7e4e [.] 0x00000000000f7de0 1
0.09% systemd-journal systemd-journald [.] free@plt [.] cfree@GLIBC_2.2.5 1
0.09% systemd-journal libc-2.29.so [.] _int_free [.] _int_free 18
0.09% systemd-journal libc-2.29.so [.] _int_free [.] _int_free 2
0.04% systemd libsystemd-shared-241.so [.] bus_resolve@plt [.] bus_resolve 204
0.04% systemd libsystemd-shared-241.so [.] getpid_cached@plt [.] getpid_cached 7
[root@seventh ~]#
Lets use -v to get full paths and then try objdump on the unresolved address:
[root@seventh ~]# perf report -v --stdio --dso libsystemd-shared-241.so |& grep libsystemd-shared-241.so | tail -1
0.04% systemd-journal /usr/lib/systemd/libsystemd-shared-241.so 0x80c1a B [.] 0x0000000000080c1a 0x80a95 B [.] 0x0000000000080a95 61
[root@seventh ~]#
[root@seventh ~]# objdump -d --start-address 0x00000000000f7d80 /usr/lib/systemd/libsystemd-shared-241.so | head -20
/usr/lib/systemd/libsystemd-shared-241.so: file format elf64-x86-64
Disassembly of section .text:
00000000000f7d80 <proc_cmdline_parse_given@@SD_SHARED+0x330>:
f7d80: 41 39 11 cmp %edx,(%r9)
f7d83: 0f 84 ff fe ff ff je f7c88 <proc_cmdline_parse_given@@SD_SHARED+0x238>
f7d89: 4c 8d 05 97 09 0c 00 lea 0xc0997(%rip),%r8 # 1b8727 <utf8_skip_data@@SD_SHARED+0x3147>
f7d90: b9 49 00 00 00 mov $0x49,%ecx
f7d95: 48 8d 15 c9 f5 0b 00 lea 0xbf5c9(%rip),%rdx # 1b7365 <utf8_skip_data@@SD_SHARED+0x1d85>
f7d9c: 31 ff xor %edi,%edi
f7d9e: 48 8d 35 9b ff 0b 00 lea 0xbff9b(%rip),%rsi # 1b7d40 <utf8_skip_data@@SD_SHARED+0x2760>
f7da5: e8 a6 d6 f4 ff callq 45450 <log_assert_failed_realm@plt>
f7daa: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1)
f7db0: 41 56 push %r14
f7db2: 41 55 push %r13
f7db4: 41 54 push %r12
f7db6: 55 push %rbp
[root@seventh ~]#
If we tried the the reported address before this patch:
[root@seventh ~]# objdump -d --start-address 0x00007fe406465d80 /usr/lib/systemd/libsystemd-shared-241.so | head -20
/usr/lib/systemd/libsystemd-shared-241.so: file format elf64-x86-64
[root@seventh ~]#
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200227043939.4403-2-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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