Commits · 2c15f5eb04e9e7e19a2c8be6b50c63a4c6062a44 · nexedi / linux

06 May, 2016 24 commits

perf script: Expose usage of the callchain db export via the python api · 2c15f5eb

Chris Phlipot authored Apr 28, 2016

This change allows python scripts to be able to utilize the recent
changes to the db export api allowing the export of call_paths derived
from sampled callchains. These call paths are also now associated with
the samples from which they were derived.

- This feature is enabled by setting "perf_db_export_callchains" to true

- When enabled, samples that have callchain information will have the
  callchains exported via call_path_table

- The call_path_id field is added to sample_table to enable association of
  samples with the corresponding callchain stored in the call paths
  table. A call_path_id of 0 will be exported if there is no
  corresponding callchain.

- When "perf_db_export_callchains" and "perf_db_export_calls" are both
  set to True, the call path root data structure will be shared. This
  prevents duplicating of data and call path ids that would result from
  building two separate call path trees in memory.

- The call_return_processor structure definition was relocated to the header
  file to make its contents visible to db-export.c. This enables the
  sharing of call path trees between the two features, as mentioned
  above.

This change is visible to python scripts using the python db export api.

The change is backwards compatible with scripts written against the
previous API, assuming that the scripts model the sample_table function
after the one in export-to-postgresql.py script by allowing for
additional arguments to be added in the future. ie. using *x as the
final argument of the sample_table function.
Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1461831551-12213-6-git-send-email-cphlipot0@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2c15f5eb

perf script: Add call path id to exported sample in db export · 568850ea

Chris Phlipot authored Apr 28, 2016

The exported sample now contains a reference to the call_path_id that
represents its callchain.

While callchains themselves are nice to have, being able to associate
them with samples makes them much more useful, and can allow for such
things as determining how much cumulative time is spent in a particular
function. This information is normally possible to get from the call
return processor. However, when doing normal sampling, call/return
information is not available, thus necessitating the need for
associating samples directly with call paths.

This commit include changes to db-export layer to make this information
available for subsequent patches in this change set, but by itself, does
not make any changes visible to the user.
Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1461831551-12213-5-git-send-email-cphlipot0@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

568850ea

perf script: Enable db export to output sampled callchains · 0a3eba3a

Chris Phlipot authored Apr 28, 2016

This change enables the db export api to export callchains. This is
accomplished by adding callchains obtained from samples to the
call_path_root structure and exporting them via the current call path
export API.

While the current API does support exporting call paths, this is not
supported when sampling. This commit addresses that missing feature by
allowing the export of call paths when callchains are present in
samples.

Summary:

- This feature is activated by initializing the call_path_root member
  inside the db_export structure to a non-null value.

- Callchains are resolved with thread__resolve_callchain() and then stored
  and exported by adding a call path under call path root.
- Symbol and DSO for each callchain node are exported via db_ids_from_al()

This commit puts in place infrastructure to be used by subsequent commits,
and by itself, does not introduce any user-visible changes.
Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1461831551-12213-4-git-send-email-cphlipot0@gmail.com
[ Made adjustments suggested by Adrian Hunter, see thread via this cset's Link: tag ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

0a3eba3a

perf tools: Refactor code to move call path handling out of thread-stack · 451db126

Chris Phlipot authored Apr 28, 2016

Move the call path handling code out of thread-stack.c and
thread-stack.h to allow other components that are not part of
thread-stack to create call paths.

Summary:

- Create call-path.c and call-path.h and add them to the build.

- Move all call path related code out of thread-stack.c and thread-stack.h
  and into call-path.c and call-path.h.

- A small subset of structures and functions are now visible through
  call-path.h, which is required for thread-stack.c to continue to
  compile.

This change is a prerequisite for subsequent patches in this change set
and by itself contains no user-visible changes.
Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1461831551-12213-3-git-send-email-cphlipot0@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

451db126

perf callchain: Fix incorrect ordering of entries · 9919a65e

Chris Phlipot authored Apr 28, 2016

The existing implementation of thread__resolve_callchain, under certain
circumstances, can assemble callchain entries in the incorrect order.

The callchain entries are resolved incorrectly for a sample when all of
the following conditions are met:

1. callchain_param.order is set to ORDER_CALLER

2. thread__resolve_callchain_sample is able to resolve callchain entries
   for the sample.

3. unwind__get_entries is also able to resolve callchain entries for the
   sample.

The fix is accomplished by reversing the order in which
thread__resolve_callchain_sample and unwind__get_entries are called when
callchain_param.order is set to ORDER_CALLER.

Unwind specific code from thread__resolve_callchain is also moved into a
new static function to improve readability of the fix.

How to Reproduce the Existing Bug:

Modifying perf script to print call trees in the opposite order or
applying the remaining patches from this series and comparing the
results output from export-to-postgtresql.py are the easiest ways to see
the bug, however it can still be seen in current builds using perf
report.

Here is how i can reproduce the bug using perf report:

  # perf record --call-graph=dwarf stress -c 1 -t 5

when i run this command:

  # perf report --call-graph=flat,0,0,callee

This callchain, containing kernel (handle_irq_event, etc) and userspace
samples (__libc_start_main, etc) is contained in the output, which looks
correct (callee order):

                gen8_irq_handler
                handle_irq_event_percpu
                handle_irq_event
                handle_edge_irq
                handle_irq
                do_IRQ
                ret_from_intr
                __random
                rand
                0x558f2a04dded
                0x558f2a04c774
                __libc_start_main
                0x558f2a04dcd9

Now run this command using caller order:

  # perf report --call-graph=flat,0,0,caller

It is expected to see the exact reverse of the above when using caller
order (with "0x558f2a04dcd9" at the top and "gen8_irq_handler" at the
bottom) in the output, but it is nowhere to be found.

instead you see this:

                ret_from_intr
                do_IRQ
                handle_irq
                handle_edge_irq
                handle_irq_event
                handle_irq_event_percpu
                gen8_irq_handler
                0x558f2a04dcd9
                __libc_start_main
                0x558f2a04c774
                0x558f2a04dded
                rand
                __random

Notice how internally the kernel symbols are reversed and the user space
symbols are reversed, but the kernel symbols still appear above the user
space symbols.

if this patch is applied and perf script is re-run, you will see the
expected output (with "0x558f2a04dcd9" at the top and "gen8_irq_handler"
at the bottom):

                0x558f2a04dcd9
                __libc_start_main
                0x558f2a04c774
                0x558f2a04dded
                rand
                __random
                ret_from_intr
                do_IRQ
                handle_irq
                handle_edge_irq
                handle_irq_event
                handle_irq_event_percpu
                gen8_irq_handler
Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1461831551-12213-2-git-send-email-cphlipot0@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

9919a65e

perf trace: Do not print raw args list for syscalls with no args · 4c4d6e51

Arnaldo Carvalho de Melo authored May 05, 2016

The test to check if the arg format had been read from the
syscall:sys_enter_name/format file was looking at the list of non-commom
fields, and if that is empty, it would think it had failed to read it,
because it doesn't exist, for instance, for the clone() syscall.

So instead before dumping the raw syscall args list check
IS_ERR(sc->tp_format), if that is true, then an attempt was made to read
the format file and failed, in which case dump the raw arg list values.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-ls7pmdqb2xy9339vdburwvnk@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

4c4d6e51

Merge tag 'perf-core-for-mingo-20160505' of... · c0edb746

Ingo Molnar authored May 06, 2016

Merge tag 'perf-core-for-mingo-20160505' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

- Order output of 'perf trace --summary' better, now the threads will
  appear ascending order of number of events, and then, for each, in
  descending order of syscalls by the time spent in the syscalls, so
  that the last page produced can be the one about the most interesting
  thread straced, suggested by Milian Wolff (Arnaldo Carvalho de Melo)

- Do not show the runtime_ms for a thread when not collecting it, that
  is done so far only with 'perf trace --sched' (Arnaldo Carvalho de Melo)

- Fix kallsyms perf test on ppc64le (Naveen N. Rao)

Infrastructure changes:

- Move global variables related to presence of some keys in the sort order to a
  per hist struct, to allow code like the hists browser to work with multiple
  hists with different lists of columns (Jiri Olsa)

- Add support for generating bpf prologue in powerpc (Naveen N. Rao)

- Fix kprobe and kretprobe handling with kallsyms on ppc64le (Naveen N. Rao)

- evlist mmap changes, prep work for supporting reading backwards (Wang Nan)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

c0edb746

perf evlist: Rename variable in perf_mmap__read() · b6b85dad

Wang Nan authored Apr 27, 2016

In perf_mmap__read(), give better names to pointers. Original name 'old'
and 'head' directly related to pointers in ring buffer control page. For
backward ring buffer, the meaning of 'head' point is not 'the first byte
of free space', but 'the first byte of the last record'. To reduce
confusion, rename 'old' to 'start', 'head' to 'end'.  'start' -> 'end'
is the direction the records should be read from.

Change parameter order.

Change 'overwrite' to 'check_messup'. When reading from 'head', no need
to check messup for for backward ring buffer.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1461723563-67451-3-git-send-email-wangnan0@huawei.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

b6b85dad

perf evlist: Extract perf_mmap__read() · 0f4ccd11

Wang Nan authored Apr 27, 2016

Extract event reader from perf_evlist__mmap_read() to perf__mmap_read().
Future commit will feed it with manually computed 'head' and 'old'
pointers.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1461723563-67451-2-git-send-email-wangnan0@huawei.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

0f4ccd11

perf symbols: Fix kallsyms perf test on ppc64le · 0b3c2264

Naveen N. Rao authored Apr 12, 2016

ppc64le functions have a Global Entry Point (GEP) and a Local Entry
Point (LEP). While placing a probe, we always prefer the LEP since it
catches function calls through both the GEP and the LEP. In order to do
this, we fixup the function entry points during elf symbol table lookup
to point to the LEPs. This works, but breaks 'perf test kallsyms' since
the symbols loaded from the symbol table (pointing to the LEP) do not
match the symbols in kallsyms.

To fix this, we do not adjust all the symbols during symbol table load.
Instead, we note down st_other in a newly introduced arch-specific
member of perf symbol structure, and later use this to adjust the probe
trace point.
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Mark Wielaard <mjw@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/6be7c2b17e370100c2f79dd444509df7929bdd3e.1460451721.git.naveen.n.rao@linux.vnet.ibm.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

0b3c2264

perf powerpc: Fix kprobe and kretprobe handling with kallsyms on ppc64le · 239aeba7

Naveen N. Rao authored Apr 12, 2016

So far, we used to treat probe point offsets as being offset from the
LEP. However, userspace applications (objdump/readelf) always show
disassembly and offsets from the function GEP. This is confusing to the
user as we will end up probing at an address different from what the
user expects when looking at the function disassembly with
readelf/objdump. Fix this by changing how we modify probe address with
perf.

If only the function name is provided, we assume the user needs the LEP.
Otherwise, if an offset is specified, we assume that the user knows the
exact address to probe based on function disassembly, and so we just
place the probe from the GEP offset.

Finally, kretprobe was also broken with kallsyms as we were trying to
specify an offset. This patch also fixes that issue.
Reported-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Mark Wielaard <mjw@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/75df860aad8216bf4b9bcd10c6351ecc0e3dee54.1460451721.git.naveen.n.rao@linux.vnet.ibm.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

239aeba7