Since commit 0a892c1c94 ("perf record: Add dummy event during system wide synthesis"),
a dummy event is added to capture mmaps.
But if we run perf-record as,
# perf record -e cycles:p -IXMM0 -a -- sleep 1
Error:
dummy:HG: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'
The issue is, if we enable the extended regs (-IXMM0), but the
pmu->capabilities is not set with PERF_PMU_CAP_EXTENDED_REGS, the kernel
will return -EOPNOTSUPP error.
See following code:
/* in kernel/events/core.c */
static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
{
....
if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
has_extended_regs(event))
ret = -EOPNOTSUPP;
....
}
For software dummy event, the PMU should not be set with
PERF_PMU_CAP_EXTENDED_REGS. But unfortunately now, the dummy
event has possibility to be set with PERF_REG_EXTENDED_MASK bit.
In evsel__config, /* tools/perf/util/evsel.c */
if (opts->sample_intr_regs) {
attr->sample_regs_intr = opts->sample_intr_regs;
}
If we use -IXMM0, the attr>sample_regs_intr will be set with
PERF_REG_EXTENDED_MASK bit.
It doesn't make sense to set attr->sample_regs_intr for a
software dummy event.
This patch adds dummy event checking before setting
attr->sample_regs_intr and attr->sample_regs_user.
After:
# ./perf record -e cycles:p -IXMM0 -a -- sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.413 MB perf.data (45 samples) ]
Committer notes:
Adrian said this when providing his Acked-by:
"
This is fine. It will not break PT.
no_aux_samples is useful for evsels that have been added by the code rather
than requested by the user. For old kernels PT adds sched_switch tracepoint
to track context switches (before the current context switch event was
added) and having auxiliary sample information unnecessarily uses up space
in the perf buffer.
"
Fixes: 0a892c1c94 ("perf record: Add dummy event during system wide synthesis")
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200720010013.18238-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Minor conflict in tools/perf/arch/arm/util/auxtrace.c as one fix there
was cherry-picked for the last perf/urgent pull req to Linus, so was
already there.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Keeping the stack of nested metrics via 'struct expr_id' objects
and checking if we are in recursion via already processed metric.
The stack is implemented as static array within the struct egroup
with 100 entries, which should be enough nesting depth for any
metric we have or plan to have at the moment.
Adding test that simulates the recursion and checks we can
detect it.
Committer notes:
Bumped RECURSION_ID_MAX to 1000 as per Jiri's reply to Paul Clark on the
patch series e-mail discussion.
Fixed these:
tests/parse-metric.c:308:7: error: missing field 'val' initializer [-Werror,-Wmissing-field-initializers]
{ 0 },
^
util/metricgroup.c:924:28: error: missing field 'parent' initializer [-Werror,-Wmissing-field-initializers]
struct expr_ids ids = { 0 };
^
util/metricgroup.c:924:26: error: suggest braces around initialization of subobject [-Werror,-Wmissing-braces]
struct expr_ids ids = { 0 };
^
{}
util/metricgroup.c:924:26: error: suggest braces around initialization of subobject [-Werror,-Wmissing-braces]
struct expr_ids ids = { 0 };
^
{}
util/metricgroup.c:924:28: error: missing field 'cnt' initializer [-Werror,-Wmissing-field-initializers]
struct expr_ids ids = { 0 };
^
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200719181320.785305-16-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Jin Yao reported issue with possible conflict between raw events and
term values in pmu event syntax.
Currently following syntax is resolved as raw event with 0xead value:
uncore_imc_free_running/read/
instead of using 'read' term from uncore_imc_free_running pmu, because
'read' is correct raw event syntax with 0xead value.
To solve this issue we do following:
- check existing terms during rXXXX syntax processing
and make them priority in case of conflict
- allow pmu/r0x1234/ syntax to be able to specify conflicting
raw event (implemented in previous patch)
Also add automated tests for this and perf_pmu__parse_cleanup call to
parse_events_terms, so the test gets properly cleaned up.
Fixes: 3a6c51e4d6 ("perf parser: Add support to specify rXXX event with pmu")
Reported-by: Jin Yao <yao.jin@linux.intel.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: http://lore.kernel.org/lkml/20200726075244.1191481-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick up the changes in:
b2f9f1535b ("libbpf: Fix libbpf hashmap on (I)LP32 architectures")
Silencing this warning:
Warning: Kernel ABI header at 'tools/perf/util/hashmap.h' differs from latest version at 'tools/lib/bpf/hashmap.h'
diff -u tools/perf/util/hashmap.h tools/lib/bpf/hashmap.h
I'll eventually update the warning to remove the "Kernel ABI" part
and instead state libbpf when noticing that the original is at
"tools/lib/something".
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Jakub Bogusz <qboosh@pld-linux.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Ian Rogers <irogers@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Warn if the probe target function is a GNU indirect function (GNU_IFUNC)
because it may not be what the user wants to probe.
The GNU indirect function ( https://sourceware.org/glibc/wiki/GNU_IFUNC )
is the dynamic symbol solved at runtime. An IFUNC function is a selector
which is invoked from the ELF loader, but the symbol address of the
function which will be modified by the IFUNC is the same as the IFUNC in
the symbol table. This can confuse users trying to probe such functions.
For example, memcpy is an IFUNC.
probe_libc:memcpy (on __new_memcpy_ifunc@x86_64/multiarch/memcpy.c in /usr/lib64/libc-2.30.so)
the probe is put on an IFUNC.
perf 1742 [000] 26201.715632: probe_libc:memcpy: (7fdaa53824c0)
7fdaa53824c0 __new_memcpy_ifunc+0x0 (inlined)
7fdaa5d4a980 elf_machine_rela+0x6c0 (inlined)
7fdaa5d4a980 elf_dynamic_do_Rela+0x6c0 (inlined)
7fdaa5d4a980 _dl_relocate_object+0x6c0 (/usr/lib64/ld-2.30.so)
7fdaa5d42155 dl_main+0x1cc5 (/usr/lib64/ld-2.30.so)
7fdaa5d5831a _dl_sysdep_start+0x54a (/usr/lib64/ld-2.30.so)
7fdaa5d3ffeb _dl_start_final+0x25b (inlined)
7fdaa5d3ffeb _dl_start+0x25b (/usr/lib64/ld-2.30.so)
7fdaa5d3f117 .annobin_rtld.c+0x7 (inlined)
And the event is invoked from the ELF loader instead of the target
program's main code.
Moreover, at this moment, we can not probe on the function which will
be selected by the IFUNC, because it is determined at runtime. But
uprobe will be prepared before running the target binary.
Thus, I decided to warn user when 'perf probe' detects that the probe
point is on an GNU IFUNC symbol. Someone who wants to probe an IFUNC
symbol to debug the IFUNC function can ignore this warning.
Committer notes:
I.e., this warning will be emitted if the probe point is an IFUNC:
"Warning: The probe function (%s) is a GNU indirect function.\n"
"Consider identifying the final function used at run time and set the probe directly on that.\n"
Complete set of steps:
# readelf -sW /lib64/libc-2.29.so | grep IFUNC | tail
22196: 0000000000109a80 183 IFUNC GLOBAL DEFAULT 14 __memcpy_chk
22214: 00000000000b7d90 191 IFUNC GLOBAL DEFAULT 14 __gettimeofday
22336: 000000000008b690 60 IFUNC GLOBAL DEFAULT 14 memchr
22350: 000000000008b9b0 89 IFUNC GLOBAL DEFAULT 14 __stpcpy
22420: 000000000008bb10 76 IFUNC GLOBAL DEFAULT 14 __strcasecmp_l
22582: 000000000008a970 60 IFUNC GLOBAL DEFAULT 14 strlen
22585: 00000000000a54d0 92 IFUNC WEAK DEFAULT 14 wmemset
22600: 000000000010b030 92 IFUNC GLOBAL DEFAULT 14 __wmemset_chk
22618: 000000000008b8a0 183 IFUNC GLOBAL DEFAULT 14 __mempcpy
22675: 000000000008ba70 76 IFUNC WEAK DEFAULT 14 strcasecmp
#
# perf probe -x /lib64/libc-2.29.so strlen
Warning: The probe function (strlen) is a GNU indirect function.
Consider identifying the final function used at run time and set the probe directly on that.
Added new event:
probe_libc:strlen (on strlen in /usr/lib64/libc-2.29.so)
You can now use it in all perf tools, such as:
perf record -e probe_libc:strlen -aR sleep 1
#
Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lore.kernel.org/lkml/159438669349.62703.5978345670436126948.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix the memory leakage in debuginfo__find_trace_events() when the probe
point is not found in the debuginfo. If there is no probe point found in
the debuginfo, debuginfo__find_probes() will NOT return -ENOENT, but 0.
Thus the caller of debuginfo__find_probes() must check the tf.ntevs and
release the allocated memory for the array of struct probe_trace_event.
The current code releases the memory only if the debuginfo__find_probes()
hits an error but not checks tf.ntevs. In the result, the memory allocated
on *tevs are not released if tf.ntevs == 0.
This fixes the memory leakage by checking tf.ntevs == 0 in addition to
ret < 0.
Fixes: ff74178350 ("perf probe: Introduce debuginfo to encapsulate dwarf information")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/159438668346.62703.10887420400718492503.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix a wrong "variable not found" warning when the probe point is not
found in the debuginfo.
Since the debuginfo__find_probes() can return 0 even if it does not find
given probe point in the debuginfo, fill_empty_trace_arg() can be called
with tf.ntevs == 0 and it can emit a wrong warning. To fix this, reject
ntevs == 0 in fill_empty_trace_arg().
E.g. without this patch;
# perf probe -x /lib64/libc-2.30.so -a "memcpy arg1=%di"
Failed to find the location of the '%di' variable at this address.
Perhaps it has been optimized out.
Use -V with the --range option to show '%di' location range.
Added new events:
probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di)
probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di)
You can now use it in all perf tools, such as:
perf record -e probe_libc:memcpy -aR sleep 1
With this;
# perf probe -x /lib64/libc-2.30.so -a "memcpy arg1=%di"
Added new events:
probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di)
probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di)
You can now use it in all perf tools, such as:
perf record -e probe_libc:memcpy -aR sleep 1
Fixes: cb40273085 ("perf probe: Trace a magic number if variable is not found")
Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Andi Kleen <ak@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/159438667364.62703.2200642186798763202.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
There is a case that several same-name symbols points to the same
address. In that case, 'perf probe' returns an error.
E.g.
# perf probe -x /lib64/libc-2.30.so -v -a "memcpy arg1=%di"
probe-definition(0): memcpy arg1=%di
symbol:memcpy file:(null) line:0 offset:0 return:0 lazy:(null)
parsing arg: arg1=%di into name:arg1 %di
1 arguments
symbol:setjmp file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:longjmp file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:longjmp_target file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:lll_lock_wait_private file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_mallopt_arena_max file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_mallopt_arena_test file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_tunable_tcache_max_bytes file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_tunable_tcache_count file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_tunable_tcache_unsorted_limit file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_mallopt_trim_threshold file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_mallopt_top_pad file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_mallopt_mmap_threshold file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_mallopt_mmap_max file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_mallopt_perturb file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_mallopt_mxfast file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_heap_new file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_arena_reuse_free_list file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_arena_reuse file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_arena_reuse_wait file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_arena_new file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_arena_retry file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_sbrk_less file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_heap_free file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_heap_less file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_tcache_double_free file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_heap_more file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_sbrk_more file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_malloc_retry file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_memalign_retry file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_mallopt_free_dyn_thresholds file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_realloc_retry file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_calloc_retry file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:memory_mallopt file:(null) line:0 offset:0 return:0 lazy:(null)
Open Debuginfo file: /usr/lib/debug/usr/lib64/libc-2.30.so.debug
Try to find probe point from debuginfo.
Opening /sys/kernel/debug/tracing//README write=0
Failed to find the location of the '%di' variable at this address.
Perhaps it has been optimized out.
Use -V with the --range option to show '%di' location range.
An error occurred in debuginfo analysis (-2).
Trying to use symbols.
Opening /sys/kernel/debug/tracing//uprobe_events write=1
Writing event: p:probe_libc/memcpy /usr/lib64/libc-2.30.so:0x914c0 arg1=%di
Writing event: p:probe_libc/memcpy /usr/lib64/libc-2.30.so:0x914c0 arg1=%di
Failed to write event: File exists
Error: Failed to add events. Reason: File exists (Code: -17)
You can see that perf tried to write completely the same probe
definition twice, which caused an error.
To fix this issue, check the symbol list and drop duplicated symbols
(which has the same symbol name and address) from it.
With this patch:
# perf probe -x /lib64/libc-2.30.so -a "memcpy arg1=%di"
Failed to find the location of the '%di' variable at this address.
Perhaps it has been optimized out.
Use -V with the --range option to show '%di' location range.
Added new events:
probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di)
probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di)
You can now use it in all perf tools, such as:
perf record -e probe_libc:memcpy -aR sleep 1
Committer notes:
Fix this build error on 32-bit arches by using PRIx64 for symbol->start,
that is an u64:
In file included from util/probe-event.c:27:
util/probe-event.c: In function 'find_probe_trace_events_from_map':
util/probe-event.c:2978:14: error: format '%lx' expects argument of type 'long unsigned int', but argument 5 has type 'u64' {aka 'long long unsigned int'} [-Werror=format=]
pr_debug("Found duplicated symbol %s @ %lx\n",
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
util/debug.h:17:21: note: in definition of macro 'pr_fmt'
#define pr_fmt(fmt) fmt
^~~
util/probe-event.c:2978:5: note: in expansion of macro 'pr_debug'
pr_debug("Found duplicated symbol %s @ %lx\n",
^~~~~~~~
Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Link: http://lore.kernel.org/lkml/159438666401.62703.15196394835032087840.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Setting the parse_events_error directly doesn't increment num_errors
causing the error message not to be displayed. Use the
parse_events__handle_error function that sets num_errors and handle
multiple errors.
Committer notes:
Ian provided a before/after upon request:
Before:
$ /tmp/perf/perf record -e /tmp/perf/util/parse-events.o
Run 'perf list' for a list of valid events
Usage: perf record [<options>] [<command>]
or: perf record [<options>] -- <command> [<options>]
-e, --event <event> event selector. use 'perf list' to list available event
After:
$ /tmp/perf/perf record -e /tmp/perf/util/parse-events.o
event syntax error: '/tmp/perf/util/parse-events.o'
\___ Failed to load /tmp/perf/util/parse-events.o: BPF object format invalid
(add -v to see detail)
Run 'perf list' for a list of valid events
Usage: perf record [<options>] [<command>]
or: perf record [<options>] -- <command> [<options>]
-e, --event <event> event selector. use 'perf list' to list available events
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: bpf@vger.kernel.org
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@chromium.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: netdev@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yonghong Song <yhs@fb.com>
Link: http://lore.kernel.org/lkml/20200707211449.3868944-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Select text poke events when available and the kernel is being traced.
Process text poke events to invalidate entries in Intel PT's instruction
cache.
Example:
The example requires kernel config:
CONFIG_PROC_SYSCTL=y
CONFIG_SCHED_DEBUG=y
CONFIG_SCHEDSTATS=y
Before:
# perf record -o perf.data.before --kcore -a -e intel_pt//k -m,64M &
# cat /proc/sys/kernel/sched_schedstats
0
# echo 1 > /proc/sys/kernel/sched_schedstats
# cat /proc/sys/kernel/sched_schedstats
1
# echo 0 > /proc/sys/kernel/sched_schedstats
# cat /proc/sys/kernel/sched_schedstats
0
# kill %1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 3.341 MB perf.data.before ]
[1]+ Terminated perf record -o perf.data.before --kcore -a -e intel_pt//k -m,64M
# perf script -i perf.data.before --itrace=e >/dev/null
Warning:
474 instruction trace errors
After:
# perf record -o perf.data.after --kcore -a -e intel_pt//k -m,64M &
# cat /proc/sys/kernel/sched_schedstats
0
# echo 1 > /proc/sys/kernel/sched_schedstats
# cat /proc/sys/kernel/sched_schedstats
1
# echo 0 > /proc/sys/kernel/sched_schedstats
# cat /proc/sys/kernel/sched_schedstats
0
# kill %1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 2.646 MB perf.data.after ]
[1]+ Terminated perf record -o perf.data.after --kcore -a -e intel_pt//k -m,64M
# perf script -i perf.data.after --itrace=e >/dev/null
Example:
The example requires kernel config:
# CONFIG_FUNCTION_TRACER is not set
Before:
# perf record --kcore -m,64M -o t1 -a -e intel_pt//k &
# perf probe __schedule
Added new event:
probe:__schedule (on __schedule)
You can now use it in all perf tools, such as:
perf record -e probe:__schedule -aR sleep 1
# perf record -e probe:__schedule -aR sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.026 MB perf.data (68 samples) ]
# perf probe -d probe:__schedule
Removed event: probe:__schedule
# kill %1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 41.268 MB t1 ]
[1]+ Terminated perf record --kcore -m,64M -o t1 -a -e intel_pt//k
# perf script -i t1 --itrace=e >/dev/null
Warning:
207 instruction trace errors
After:
# perf record --kcore -m,64M -o t1 -a -e intel_pt//k &
# perf probe __schedule
Added new event:
probe:__schedule (on __schedule)
You can now use it in all perf tools, such as:
perf record -e probe:__schedule -aR sleep 1
# perf record -e probe:__schedule -aR sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.028 MB perf.data (107 samples) ]
# perf probe -d probe:__schedule
Removed event: probe:__schedule
# kill %1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 39.978 MB t1 ]
[1]+ Terminated perf record --kcore -m,64M -o t1 -a -e intel_pt//k
# perf script -i t1 --itrace=e >/dev/null
# perf script -i t1 --no-itrace -D | grep 'POKE\|KSYMBOL'
6 565303693547 0x291f18 [0x50]: PERF_RECORD_KSYMBOL addr ffffffffc027a000 len 4096 type 2 flags 0x0 name kprobe_insn_page
6 565303697010 0x291f68 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffc027a000 old len 0 new len 6
6 565303838278 0x291fa8 [0x50]: PERF_RECORD_KSYMBOL addr ffffffffc027c000 len 4096 type 2 flags 0x0 name kprobe_optinsn_page
6 565303848286 0x291ff8 [0xa0]: PERF_RECORD_TEXT_POKE addr 0xffffffffc027c000 old len 0 new len 106
6 565369336743 0x292af8 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffff88ab8890 old len 5 new len 5
7 566434327704 0x217c208 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffff88ab8890 old len 5 new len 5
6 566456313475 0x293198 [0xa0]: PERF_RECORD_TEXT_POKE addr 0xffffffffc027c000 old len 106 new len 0
6 566456314935 0x293238 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffc027a000 old len 6 new len 0
Example:
The example requires kernel config:
CONFIG_FUNCTION_TRACER=y
Before:
# perf record --kcore -m,64M -o t1 -a -e intel_pt//k &
# perf probe __kmalloc
Added new event:
probe:__kmalloc (on __kmalloc)
You can now use it in all perf tools, such as:
perf record -e probe:__kmalloc -aR sleep 1
# perf record -e probe:__kmalloc -aR sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.022 MB perf.data (6 samples) ]
# perf probe -d probe:__kmalloc
Removed event: probe:__kmalloc
# kill %1
[ perf record: Woken up 2 times to write data ]
[ perf record: Captured and wrote 43.850 MB t1 ]
[1]+ Terminated perf record --kcore -m,64M -o t1 -a -e intel_pt//k
# perf script -i t1 --itrace=e >/dev/null
Warning:
8 instruction trace errors
After:
# perf record --kcore -m,64M -o t1 -a -e intel_pt//k &
# perf probe __kmalloc
Added new event:
probe:__kmalloc (on __kmalloc)
You can now use it in all perf tools, such as:
perf record -e probe:__kmalloc -aR sleep 1
# perf record -e probe:__kmalloc -aR sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.037 MB perf.data (206 samples) ]
# perf probe -d probe:__kmalloc
Removed event: probe:__kmalloc
# kill %1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 41.442 MB t1 ]
[1]+ Terminated perf record --kcore -m,64M -o t1 -a -e intel_pt//k
# perf script -i t1 --itrace=e >/dev/null
# perf script -i t1 --no-itrace -D | grep 'POKE\|KSYMBOL'
5 312216133258 0x8bafe0 [0x50]: PERF_RECORD_KSYMBOL addr ffffffffc0360000 len 415 type 2 flags 0x0 name ftrace_trampoline
5 312216133494 0x8bb030 [0x1d8]: PERF_RECORD_TEXT_POKE addr 0xffffffffc0360000 old len 0 new len 415
5 312216229563 0x8bb208 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffac6016f5 old len 5 new len 5
5 312216239063 0x8bb248 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffac601803 old len 5 new len 5
5 312216727230 0x8bb288 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffabbea190 old len 5 new len 5
5 312216739322 0x8bb2c8 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffac6016f5 old len 5 new len 5
5 312216748321 0x8bb308 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffac601803 old len 5 new len 5
7 313287163462 0x2817430 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffac6016f5 old len 5 new len 5
7 313287174890 0x2817470 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffac601803 old len 5 new len 5
7 313287818979 0x28174b0 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffabbea190 old len 5 new len 5
7 313287829357 0x28174f0 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffac6016f5 old len 5 new len 5
7 313287841246 0x2817530 [0x40]: PERF_RECORD_TEXT_POKE addr 0xffffffffac601803 old len 5 new len 5
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: x86@kernel.org
Link: http://lore.kernel.org/lkml/20200512121922.8997-14-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Our local MSAN (Memory Sanitizer) build of perf throws a warning that
comes from the "dso__disassemble_filename" function in
"tools/perf/util/annotate.c" when running perf record.
The warning stems from the call to readlink, in which "build_id_path"
was being read into "linkname". Since readlink does not null terminate,
an uninitialized memory access would later occur when "linkname" is
passed into the strstr function. This is simply fixed by
null-terminating "linkname" after the call to readlink.
To reproduce this warning, build perf by running:
$ make -C tools/perf CLANG=1 CC=clang EXTRA_CFLAGS="-fsanitize=memory -fsanitize-memory-track-origins"
(Additionally, llvm might have to be installed and clang might have to
be specified as the compiler - export CC=/usr/bin/clang)
Then running:
tools/perf/perf record -o - ls / | tools/perf/perf --no-pager annotate -i - --stdio
Please see the cover letter for why false positive warnings may be
generated.
Signed-off-by: Numfor Mbiziwo-Tiapo <nums@google.com>
Acked-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Drayton <mbd@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20190729205750.193289-1-nums@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
**perf-<pid>.map and jit-<pid>.dump designs:
When a JIT generates code to be executed, it must allocate memory and
mark it executable using an mmap call.
*** perf-<pid>.map design
The perf-<pid>.map assumes that any sample recorded in an anonymous
memory page is JIT code. It then tries to resolve the symbol name by
looking at the process' perf-<pid>.map.
*** jit-<pid>.dump design
The jit-<pid>.dump mechanism takes a different approach. It requires a
JIT to write a `<path>/jit-<pid>.dump` file. This file must also be
mmapped so that perf inject -jit can find the file. The JIT must also
add JIT_CODE_LOAD records for any functions it generates. The records
are timestamped using a clock which can be correlated to the perf record
clock.
After perf record, the `perf inject -jit` pass parses the recording
looking for a `<path>/jit-<pid>.dump` file. When it finds the file, it
parses it and for each JIT_CODE_LOAD record:
* creates an elf file `<path>/jitted-<pid>-<code_index>.so
* injects a new mmap record mapping the new elf file into the process.
*** Coexistence design
The kernel and perf support both of these mechanisms. We need to make
sure perf works on an app supporting either or both of these mechanisms.
Both designs rely on mmap records to determine how to resolve an ip
address.
The mmap records of both techniques by definition overlap. When the JIT
compiles a method, it must:
* allocate memory (mmap)
* add execution privilege (mprotect or mmap. either will
generate an mmap event form the kernel to perf)
* compile code into memory
* add a function record to perf-<pid>.map and/or jit-<pid>.dump
Because the jit-<pid>.dump mechanism supports greater capabilities, perf
prefers the symbols from jit-<pid>.dump. It implements this based on
timestamp ordering of events. There is an implicit ASSUMPTION that the
JIT_CODE_LOAD record timestamp will be after the // anon mmap event that
was generated during memory allocation or adding the execution privilege setting.
*** Problems with the ASSUMPTION
The ASSUMPTION made in the Coexistence design section above is violated
in the following scenario.
*** Scenario
While a JIT is jitting code it will eventually need to commit more
pages and change these pages to executable permissions. Typically the
JIT will want these collocated to minimize branch displacements.
The kernel will coalesce these anonymous mapping with identical
permissions before sending an MMAP event for the new pages. The address
range of the new mmap will not be just the most recently mmap pages.
It will include the entire coalesced mmap region.
See mm/mmap.c
unsigned long mmap_region(struct file *file, unsigned long addr,
unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
struct list_head *uf)
{
...
/*
* Can we just expand an old mapping?
*/
...
perf_event_mmap(vma);
...
}
*** Symptoms
The coalesced // anon mmap event will be timestamped after the
JIT_CODE_LOAD records. This means it will be used as the most recent
mapping for that entire address range. For remaining events it will look
at the inferior perf-<pid>.map for symbols.
If both mechanisms are supported, the symbol will appear twice with
different module names. This causes weird behavior in reporting.
If only jit-<pid>.dump is supported, the symbol will no longer be resolved.
** Implemented solution
This patch solves the issue by removing // anon mmap events for any
process which has a valid jit-<pid>.dump file.
It tracks on a per process basis to handle the case where some running
apps support jit-<pid>.dump, but some only support perf-<pid>.map.
It adds new assumptions:
* // anon mmap events are only required for perf-<pid>.map support.
* An app that uses jit-<pid>.dump, no longer needs
perf-<pid>.map support. It assumes that any perf-<pid>.map info is
inferior.
*** Details
Use thread->priv to store whether a jitdump file has been processed
During "perf inject --jit", discard "//anon*" mmap events for any pid which
has sucessfully processed a jitdump file.
** Testing:
// jitdump case
perf record <app with jitdump>
perf inject --jit --input perf.data --output perfjit.data
// verify mmap "//anon" events present initially
perf script --input perf.data --show-mmap-events | grep '//anon'
// verify mmap "//anon" events removed
perf script --input perfjit.data --show-mmap-events | grep '//anon'
// no jitdump case
perf record <app without jitdump>
perf inject --jit --input perf.data --output perfjit.data
// verify mmap "//anon" events present initially
perf script --input perf.data --show-mmap-events | grep '//anon'
// verify mmap "//anon" events not removed
perf script --input perfjit.data --show-mmap-events | grep '//anon'
** Repro:
This issue was discovered while testing the initial CoreCLR jitdump
implementation. https://github.com/dotnet/coreclr/pull/26897.
** Alternate solutions considered
These were also briefly considered:
* Change kernel to not coalesce mmap regions.
* Change kernel reporting of coalesced mmap regions to perf. Only
include newly mapped memory.
* Only strip parts of // anon mmap events overlapping existing
jitted-<pid>-<code_index>.so mmap events.
Signed-off-by: Steve MacLean <Steve.MacLean@Microsoft.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/1590544271-125795-1-git-send-email-steve.maclean@linux.microsoft.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick up fixes and move perf/core forward, minor conflict as
perf_evlist__add_dummy() lost its 'perf_' prefix as it operates on a
'struct evlist', not on a 'struct perf_evlist', i.e. its tools/perf/
specific, it is not in libperf.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When recording PEBS-via-PT, the kernel will not accept the intel_pt
event with register sampling e.g.
# perf record --kcore -c 10000 -e '{intel_pt/branch=0/,branch-loads/aux-output/ppp}' -I -- ls -l
Error:
intel_pt/branch=0/: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'
Fix by suppressing register sampling on the intel_pt evsel.
Committer notes:
Adrian informed that this is only available from Tremont onwards, so on
older processors the error continues the same as before.
Fixes: 9e64cefe43 ("perf intel-pt: Process options for PEBS event synthesis")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Luwei Kang <luwei.kang@intel.com>
Link: http://lore.kernel.org/lkml/20200630133935.11150-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Commit 0a892c1c94 ("perf record: Add dummy event during system wide
synthesis") reveals an issue with Intel PT system wide tracing.
Specifically that Intel PT already adds a dummy tracking event, and it
is not the first event. Adding another dummy tracking event causes
duplicated sideband events. Fix by checking for an existing dummy
tracking event first.
Example showing duplicated switch events:
Before:
# perf record -a -e intel_pt//u uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.895 MB perf.data ]
# perf script --no-itrace --show-switch-events | head
swapper 0 [007] 6390.516222: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 11/11
swapper 0 [007] 6390.516222: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 11/11
rcu_sched 11 [007] 6390.516223: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
rcu_sched 11 [007] 6390.516224: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
rcu_sched 11 [007] 6390.516227: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
rcu_sched 11 [007] 6390.516227: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [007] 6390.516228: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11/11
swapper 0 [007] 6390.516228: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11/11
swapper 0 [002] 6390.516415: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 5556/5559
swapper 0 [002] 6390.516416: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 5556/5559
After:
# perf record -a -e intel_pt//u uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.868 MB perf.data ]
# perf script --no-itrace --show-switch-events | head
swapper 0 [005] 6450.567013: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 7179/7181
perf 7181 [005] 6450.567014: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
perf 7181 [005] 6450.567028: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [005] 6450.567029: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 7179/7181
swapper 0 [005] 6450.571699: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 11/11
rcu_sched 11 [005] 6450.571700: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
rcu_sched 11 [005] 6450.571702: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [005] 6450.571703: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11/11
swapper 0 [005] 6450.579703: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 11/11
rcu_sched 11 [005] 6450.579704: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20200629091955.17090-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
