Occassionally events (e.g., context-switch, sched tracepoints) are losing
the conversion of sample data associated with a thread. For example:
$ perf record -e sched:sched_switch -c 1 -a -- sleep 5
$ perf script
<selected events shown>
ls 30482 [000] 1379727.583037: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
ls 30482 [000] 1379727.586339: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
:30482 30482 [000] 1379727.589462: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
The last line lost the conversion from tid to comm. If you look at the events
(perf script -D) you see why - a SAMPLE event is generated after the EXIT:
0 1379727589449774 0x1540b0 [0x38]: PERF_RECORD_EXIT(30482:30482):(30482:30482)
0 1379727589462497 0x1540e8 [0x80]: PERF_RECORD_SAMPLE(IP, 1): 30482/30482: 0xffffffff816416f1 period: 1 addr: 0
... thread: :30482:30482
When perf processes the EXIT event the thread is moved to the dead_threads
list. When the SAMPLE event is processed no thread exists for the pid so a new
one is created by machine__findnew_thread.
This patch address the problem by delaying the move to the dead_threads list
until the tid is re-used (per Adrian's suggestion).
With this patch we get the previous example shows:
ls 30482 [000] 1379727.583037: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
ls 30482 [000] 1379727.586339: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
ls 30482 [000] 1379727.589462: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
and
0 1379727589449774 0x1540b0 [0x38]: PERF_RECORD_EXIT(30482:30482):(30482:30482)
0 1379727589462497 0x1540e8 [0x80]: PERF_RECORD_SAMPLE(IP, 1): 30482/30482: 0xffffffff816416f1 period: 1 addr: 0
... thread: ls:30482
v4: per Arnaldo's request add dead flag to thread struct and set when task exits
v3: re-do from a time based check to a delayed move to dead_threads list
v2: Rebased to latest perf/core branch. Changed time comparison to use
a macro which explicitly shows the time basis
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1376491767-84171-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf stat -a needs 10 open file descriptors per logical CPU
perf stat -a -dddd needs 20 open fds for each.
This implies that stat -a doesn't work on any system with the default
ulimit -n 1024 which has more than ~100 CPUs and stat -a -dddd doesn't
work on anything with more than 46 CPUs.
Longer term there needs to be probably some way to lower the file
descriptor requirements. This would need some changes in the kernel/user
interface.
But short term this patch just tries to increase the file descriptor
limit in perf itself, when it runs into a EMFILE.
It first sets it to the hard limit, and then tries to increase the hard
limit.
On Fedora systems the default seems to be soft limit 1024 and hard limit
4*1024. So even non root can support 409 or 186 CPUs respectively. root
can go far higher.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1375670486-15480-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
For some types of work loads and special guest environments, you might
have a kernel that has no kernel modules. The perf kvm record tool
fails instantiate vmlinux maps when the kernel modules directory cannot
be opened, even though the kallsyms has been properly processed. This
leads to a perf kvm report that has no guest symbols resolved.
This patch changes the failure to locate kernel modules to be non-fatal.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373920073-4874-1-git-send-email-jason.wessel@windriver.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit adds support for a new modifier "D", which requests that the
event, or group of events, be pinned to the PMU.
The "p" modifier is already taken for precise, and "P" may be used in
future to mean "fully precise".
So we use "D", which stands for pinneD - and looks like a padlock, or if
you're using the ":D" syntax perf smiles at you.
This is an oft-requested feature from our HW folks, who want to be able
to run a large number of events, but also want 100% accurate results for
instructions per cycle.
Comparison of results with and without pinning:
$ perf stat -e '{cycles,instructions}:D' -e cycles,instructions,...
79,590,480,683 cycles # 0.000 GHz
166,123,716,524 instructions # 2.09 insns per cycle
# 0.11 stalled cycles per insn
79,352,134,463 cycles # 0.000 GHz [11.11%]
165,178,301,818 instructions # 2.08 insns per cycle
# 0.11 stalled cycles per insn [11.13%]
As you can see although perf does a very good job of scaling the values
in the non-pinned case, there is some small discrepancy.
The patch is fairly straight forward, the one detail is that we need to
make sure we only request pinning for the group leader when we have a
group.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1375795686-4226-1-git-send-email-michael@ellerman.id.au
[ Use perf_evsel__is_group_leader instead of open coded equivalent, as
suggested by Jiri Olsa ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The new "object code reading" test shows that it is not possible to read
object code from vmlinux. That is because the mappings do not map to
the dso. This patch fixes that.
A side-effect of changing the kernel map is that the "reloc" offset must
be taken into account. As a result of that separate map functions for
relocation are no longer needed.
Also fixing up the maps to match the symbols no longer makes sense and
so is not done.
The vmlinux dso data_type is now set to either DSO_BINARY_TYPE__VMLINUX
or DSO_BINARY_TYPE__GUEST_VMLINUX as approprite, which enables the
correct file name to be determined by dso__binary_type_file().
This patch breaks the "vmlinux symtab matches kallsyms" test. That is
fixed in a following patch.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1375875537-4509-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Symbol offset is one of the fields that can be requested in perf-script.
Currently you do not get that data when requested. e.g.,
perf script -f comm,tid,pid,time,cpu,sym,symoff,ip
...
gcc 6201/6201 [006] 762250.617897:
ffffffff81090d95 update_curr
ffffffff810911b8 dequeue_entity
ffffffff81091825 dequeue_task_fair
ffffffff81087163 dequeue_task
ffffffff81087c03 deactivate_task
...
With this patch you get the offset:
...
gcc 6201/6201 [006] 762250.617897:
ffffffff81090d95 update_curr+0x1c5
ffffffff810911b8 dequeue_entity+0x28
ffffffff81091825 dequeue_task_fair+0x45
ffffffff81087163 dequeue_task+0x93
ffffffff81087c03 deactivate_task+0x23
...
Signed-off-by: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/1375024474-45726-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Adding 'S' event/group modifier to specify that the event value/s are
read by PERF_SAMPLE_READ sample type processing, instead of the period
value offered by lower layers.
There's additional behaviour change for 'S' modifier being specified on
event group:
Currently all the events within a group makes samples. If user now
specifies 'S' within group modifier, only the leader will trigger
samples. The rest of events in the group will have sampling disabled.
And same as for single events, values of all events within the group
(including leader) are read by PERF_SAMPLE_READ sample type processing.
Following example will create event group with cycles and cache-misses
events, setting the cycles as group leader and the only event to
actually sample. Both cycles and cache-misses event period values are
read by PERF_SAMPLE_READ sample type processing with PERF_FORMAT_GROUP
read format.
Example:
$ perf record -e '{cycles,cache-misses}:S' ls
...
$ perf report --group --show-total-period --stdio
...
# Samples: 36 of event 'anon group { cycles, cache-misses }'
# Event count (approx.): 12585593
#
# Overhead Period Command Shared Object Symbol
# .............. .............. ....... ................. ..........................
#
19.92% 1.20% 2505936 31 ls [kernel.kallsyms] [k] mark_held_locks
13.74% 0.47% 1729327 12 ls [kernel.kallsyms] [k] sched_clock_local
13.64% 23.72% 1716147 612 ls ld-2.14.90.so [.] check_match.10805
13.12% 23.22% 1650778 599 ls libc-2.14.90.so [.] _nl_intern_locale_data
11.24% 29.19% 1414554 753 ls [kernel.kallsyms] [k] sched_clock_cpu
8.50% 0.35% 1070150 9 ls [kernel.kallsyms] [k] check_chain_key
...
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-iyoinu3axi11mymwnh2b7fxj@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This is a partial revert of Namhyung's patch
afab87b91f
perf sort: Separate out memory-specific sort keys
He wrote
For global/local weights, I'm not entirely sure to place them into the
memory dimension. But it's the only user at this time.
Well TSX is another (in fact the original) user of the flags, and it
needs them to be common. So move local/global weight back to the common
sort keys.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Link: http://lkml.kernel.org/r/1374188333-17899-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
With programs with very large functions it can be useful to distinguish
the callgraph nodes on more than just function names. So for example if
you have multiple calls to the same function, it ends up being separate
nodes in the chain.
This patch adds a new key field to the callgraph options, that allows
comparing nodes on functions (as today, default) and addresses.
Longer term it would be nice to also handle src lines, but that would
need more changes and address is a reasonable proxy for it today.
I right now reference the global params, as there was no simple way to
register a params pointer.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-0uskktybf0e7wrnoi5e9b9it@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Some systems (e.g., VMs on qemu-0.13 with the default vcpu model) report
an unsupported CPU model:
Performance Events: unsupported p6 CPU model 2 no PMU driver, software events only.
Subsequent invocations of perf fail with:
The sys_perf_event_open() syscall returned with 19 (No such device) for event (cycles).
/bin/dmesg may provide additional information.
No CONFIG_PERF_EVENTS=y kernel support configured?
Add ENODEV to the list of errno's to fallback to cpu-clock.
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374190079-28507-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
