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'perf probe' uses ref_reloc_sym to adjust symbol offset address from
debuginfo address or ref_reloc_sym based address, but that is misusing
reloc_sym->addr and reloc_sym->unrelocated_addr. If map is not
relocated (map->reloc == 0), we can use reloc_sym->addr as unrelocated
address instead of reloc_sym->unrelocated_addr.
This usually does not happen. If we have a non-stripped ELF binary, we
will use it for map and debuginfo, if not, we use only kallsyms without
debuginfo. Thus, the map is always relocated (ELF and DWARF binary) or
not relocated (kallsyms).
However, if we allow the combination of debuginfo and kallsyms based map
(like using debuginfod), we have to check the map->reloc and choose the
collect address of reloc_sym.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Frank Ch. Eigler <fche@redhat.com>
Cc: Aaron Merey <amerey@redhat.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Link: http://lore.kernel.org/lkml/160041609047.912668.14314639291419159274.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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A context_switch event can have no tid because pids can be detached from
a task while the task is still running (in do_exit()). Note this won't
happen with per-task contexts because then tracing stops at
perf_event_exit_task()
If a task with no tid gets preempted, or a dying task gets preempted and
its parent releases it, when it subsequently gets switched back in,
Intel PT will not be able to determine what task is running and prints
an error "context_switch event has no tid". However, it is not really an
error because the task is in kernel space and the decoder can continue
to decode successfully. Fix by changing the error to be only a logged
message, and make allowance for tid == -1.
Example:
Using 5.9-rc4 with Preemptible Kernel (Low-Latency Desktop) e.g.
$ uname -r
5.9.0-rc4
$ grep PREEMPT .config
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
CONFIG_PREEMPT=y
CONFIG_PREEMPT_COUNT=y
CONFIG_PREEMPTION=y
CONFIG_PREEMPT_RCU=y
CONFIG_PREEMPT_NOTIFIERS=y
CONFIG_DRM_I915_PREEMPT_TIMEOUT=640
CONFIG_DEBUG_PREEMPT=y
# CONFIG_PREEMPT_TRACER is not set
# CONFIG_PREEMPTIRQ_DELAY_TEST is not set
Before:
$ cat forkit.c
#include <sys/types.h>
#include <unistd.h>
#include <sys/wait.h>
int main()
{
pid_t child;
int status = 0;
child = fork();
if (child == 0)
return 123;
wait(&status);
return 0;
}
$ gcc -o forkit forkit.c
$ sudo ~/bin/perf record --kcore -a -m,64M -e intel_pt/cyc/k &
[1] 11016
$ taskset 2 ./forkit
$ sudo pkill perf
$ [ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 17.262 MB perf.data ]
[1]+ Terminated sudo ~/bin/perf record --kcore -a -m,64M -e intel_pt/cyc/k
$ sudo ~/bin/perf script --show-task-events --show-switch-events --itrace=iqqe-o -C 1 --ns | grep -C 2 forkit
context_switch event has no tid
taskset 11019 [001] 66663.270045029: 1 instructions:k: ffffffffb1d9f844 strnlen_user+0xb4 ([kernel.kallsyms])
taskset 11019 [001] 66663.270201816: 1 instructions:k: ffffffffb1a83121 unmap_page_range+0x561 ([kernel.kallsyms])
forkit 11019 [001] 66663.270327553: PERF_RECORD_COMM exec: forkit:11019/11019
forkit 11019 [001] 66663.270420028: 1 instructions:k: ffffffffb1db9537 __clear_user+0x27 ([kernel.kallsyms])
forkit 11019 [001] 66663.270648704: 1 instructions:k: ffffffffb18829e6 do_user_addr_fault+0xf6 ([kernel.kallsyms])
forkit 11019 [001] 66663.270833163: 1 instructions:k: ffffffffb230a825 irqentry_exit_to_user_mode+0x15 ([kernel.kallsyms])
forkit 11019 [001] 66663.271092359: 1 instructions:k: ffffffffb1aea3d9 lock_page_memcg+0x9 ([kernel.kallsyms])
forkit 11019 [001] 66663.271207092: PERF_RECORD_FORK(11020:11020):(11019:11019)
forkit 11019 [001] 66663.271234775: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 11020/11020
forkit 11020 [001] 66663.271238407: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11019/11019
forkit 11020 [001] 66663.271312066: 1 instructions:k: ffffffffb1a88140 handle_mm_fault+0x10 ([kernel.kallsyms])
forkit 11020 [001] 66663.271476225: PERF_RECORD_EXIT(11020:11020):(11019:11019)
forkit 11020 [001] 66663.271497488: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 11019/11019
forkit 11019 [001] 66663.271500523: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11020/11020
forkit 11019 [001] 66663.271517241: 1 instructions:k: ffffffffb24012cd error_entry+0x6d ([kernel.kallsyms])
forkit 11019 [001] 66663.271664080: PERF_RECORD_EXIT(11019:11019):(1386:1386)
After:
$ sudo ~/bin/perf script --show-task-events --show-switch-events --itrace=iqqe-o -C 1 --ns | grep -C 2 forkit
taskset 11019 [001] 66663.270045029: 1 instructions:k: ffffffffb1d9f844 strnlen_user+0xb4 ([kernel.kallsyms])
taskset 11019 [001] 66663.270201816: 1 instructions:k: ffffffffb1a83121 unmap_page_range+0x561 ([kernel.kallsyms])
forkit 11019 [001] 66663.270327553: PERF_RECORD_COMM exec: forkit:11019/11019
forkit 11019 [001] 66663.270420028: 1 instructions:k: ffffffffb1db9537 __clear_user+0x27 ([kernel.kallsyms])
forkit 11019 [001] 66663.270648704: 1 instructions:k: ffffffffb18829e6 do_user_addr_fault+0xf6 ([kernel.kallsyms])
forkit 11019 [001] 66663.270833163: 1 instructions:k: ffffffffb230a825 irqentry_exit_to_user_mode+0x15 ([kernel.kallsyms])
forkit 11019 [001] 66663.271092359: 1 instructions:k: ffffffffb1aea3d9 lock_page_memcg+0x9 ([kernel.kallsyms])
forkit 11019 [001] 66663.271207092: PERF_RECORD_FORK(11020:11020):(11019:11019)
forkit 11019 [001] 66663.271234775: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 11020/11020
forkit 11020 [001] 66663.271238407: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11019/11019
forkit 11020 [001] 66663.271312066: 1 instructions:k: ffffffffb1a88140 handle_mm_fault+0x10 ([kernel.kallsyms])
forkit 11020 [001] 66663.271476225: PERF_RECORD_EXIT(11020:11020):(11019:11019)
forkit 11020 [001] 66663.271497488: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 11019/11019
forkit 11019 [001] 66663.271500523: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11020/11020
forkit 11019 [001] 66663.271517241: 1 instructions:k: ffffffffb24012cd error_entry+0x6d ([kernel.kallsyms])
forkit 11019 [001] 66663.271664080: PERF_RECORD_EXIT(11019:11019):(1386:1386)
forkit 11019 [001] 66663.271688752: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: -1/-1
:-1 -1 [001] 66663.271692086: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11019/11019
:-1 -1 [001] 66663.271707466: 1 instructions:k: ffffffffb18eb096 update_load_avg+0x306 ([kernel.kallsyms])
Fixes: 86c2786994bd7c ("perf intel-pt: Add support for PERF_RECORD_SWITCH")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lore.kernel.org/lkml/20200909084923.9096-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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The kernel can release tasks while they are still running. This can
result in a task having no tid, in which case perf records a tid of -1.
Improve the perf script output in that case.
Example:
Before:
# cat ./autoreap.c
#include <sys/types.h>
#include <unistd.h>
#include <sys/wait.h>
#include <signal.h>
struct sigaction act = {
.sa_handler = SIG_IGN,
};
int main()
{
pid_t child;
int status = 0;
sigaction(SIGCHLD, &act, NULL);
child = fork();
if (child == 0)
return 123;
wait(&status);
return 0;
}
# gcc -o autoreap autoreap.c
# ./perf record -a -e dummy --switch-events ./autoreap
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.948 MB perf.data ]
# ./perf script --show-task-events --show-switch-events | grep -C2 'autoreap\|4294967295\|-1'
swapper 0 [004] 18462.673613: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 25189/25189
perf 25189 [004] 18462.673614: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
autoreap 25189 [004] 18462.673800: PERF_RECORD_COMM exec: autoreap:25189/25189
autoreap 25189 [004] 18462.674042: PERF_RECORD_FORK(25191:25191):(25189:25189)
autoreap 25189 [004] 18462.674050: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [004] 18462.674051: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 25189/25189
swapper 0 [005] 18462.674083: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 25191/25191
autoreap 25191 [005] 18462.674084: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
swapper 0 [003] 18462.674121: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 11/11
rcu_preempt 11 [003] 18462.674121: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
rcu_preempt 11 [003] 18462.674124: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [003] 18462.674124: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11/11
autoreap 25191 [005] 18462.674138: PERF_RECORD_EXIT(25191:25191):(25189:25189)
PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [005] 18462.674149: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 4294967295/4294967295
swapper 0 [004] 18462.674182: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 25189/25189
autoreap 25189 [004] 18462.674183: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
autoreap 25189 [004] 18462.674218: PERF_RECORD_EXIT(25189:25189):(25188:25188)
autoreap 25189 [004] 18462.674225: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [004] 18462.674226: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 25189/25189
swapper 0 [007] 18462.674257: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 25188/25188
After:
# ./perf script --show-task-events --show-switch-events | grep -C2 'autoreap\|4294967295\|-1'
swapper 0 [004] 18462.673613: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 25189/25189
perf 25189 [004] 18462.673614: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
autoreap 25189 [004] 18462.673800: PERF_RECORD_COMM exec: autoreap:25189/25189
autoreap 25189 [004] 18462.674042: PERF_RECORD_FORK(25191:25191):(25189:25189)
autoreap 25189 [004] 18462.674050: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [004] 18462.674051: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 25189/25189
swapper 0 [005] 18462.674083: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 25191/25191
autoreap 25191 [005] 18462.674084: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
swapper 0 [003] 18462.674121: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 11/11
rcu_preempt 11 [003] 18462.674121: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
rcu_preempt 11 [003] 18462.674124: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [003] 18462.674124: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11/11
autoreap 25191 [005] 18462.674138: PERF_RECORD_EXIT(25191:25191):(25189:25189)
:-1 -1 [005] 18462.674149: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [005] 18462.674149: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: -1/-1
swapper 0 [004] 18462.674182: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 25189/25189
autoreap 25189 [004] 18462.674183: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
autoreap 25189 [004] 18462.674218: PERF_RECORD_EXIT(25189:25189):(25188:25188)
autoreap 25189 [004] 18462.674225: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [004] 18462.674226: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 25189/25189
swapper 0 [007] 18462.674257: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 25188/25188
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lore.kernel.org/lkml/20200909084923.9096-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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perf has many undocumented options, such as:-vv, --exec-path,
--html-path, -p, --paginate,--no-pager, --debugfs-dir, --buildid-dir,
--list-cmds, --list-opts.
Add entris for these options in perf.txt.
Signed-off-by: Zejiang Tang <tangzejiang@loongson.cn>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Link: http://lore.kernel.org/lkml/1599645194-8438-1-git-send-email-tangzejiang@loongson.cn
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Remove duplicate header which is included twice.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200915081541.41004-1-yuehaibing@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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