linux.git/tools/perf/util/db-export.c, branch v4.19

perf symbols: Unify symbol maps

2018-04-27T13:47:06+00:00

Remove the split of symbol tables for data (MAP__VARIABLE) and for
functions (MAP__FUNCTION), its unneeded and there were various places
doing two lookups to find a symbol, so simplify this.

We still will consider only the symbols that matched the filters in
place, i.e. see the (elf_(sec,sym)|symbol_type)__filter() routines in
the patch, just so that we consider only the same symbols as before,
to reduce the possibility of regressions.

All the tests on 50-something build environments, in varios versions
of lots of distros and cross build environments were performed without
build regressions, as usual with all pull requests the other tests were
also performed: 'perf test' and 'make -C tools/perf build-test'.

Also this was done at a great granularity so that regressions can be
bisected more easily.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: https://lkml.kernel.org/n/tip-hiq0fy2rsleupnqqwuojo1ne@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Store the ELF symbol type in the symbol struct

2018-04-26T16:47:18+00:00

There is code that needs to see if a resolved address is a function, so,
since we're going to ditch the MAP__{FUNCTION,VARIABLE} split, store
that info in the per symbol struct.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: https://lkml.kernel.org/n/tip-9ugwxz0i8ryg5702rx8u5q6z@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Remove map_type arg from dso__find_symbol()

2018-04-26T16:47:15+00:00

One more step to ditch MAP__{VARIABLE,FUNCTION}

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: https://lkml.kernel.org/n/tip-919d1k13ts62pjipnpibvgwd@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Adopt get_main_thread from db-export.c

2016-05-30T15:41:43+00:00

Move the get_main_thread function from db-export.c to thread.c so that
it can be used elsewhere.

Signed-off-by: Andi Kleen 
Cc: Jiri Olsa 
Link: http://lkml.kernel.org/r/1464051145-19968-2-git-send-email-andi@firstfloor.org
[ Removed leftover bits from db-export.h ]
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix usage of max_stack sysctl

2016-05-20T14:43:56+00:00

We cannot limit processing stacks from the current value of the sysctl,
as we may be processing perf.data files, possibly from other machines.

Instead use the old PERF_MAX_STACK_DEPTH, the sysctl default, that can
be overriden using --max-stack or equivalent.

Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Alexei Starovoitov 
Cc: Brendan Gregg 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: He Kuang 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Milian Wolff 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Cc: Wang Nan 
Cc: Zefan Li 
Fixes: 4cb93446c587 ("perf tools: Set the maximum allowed stack from /proc/sys/kernel/perf_event_max_stack")
Link: http://lkml.kernel.org/n/tip-eqeutsr7n7wy0c36z24ytvii@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf script: Fix export of callchains with recursion in db-export

2016-05-11T15:24:58+00:00

When an IP with an unresolved symbol occurs in the callchain more than
once (ie. recursion), then duplicate symbols can be created because
the callchain nodes are never updated after they are first created.

To fix this issue we call dso__find_symbol whenever we encounter a NULL
symbol, in case we already added a symbol at that IP since we started
traversing the callchain.

This change prevents duplicate symbols from being exported when duplicate
IPs are present in the callchain.

Signed-off-by: Chris Phlipot 
Cc: Adrian Hunter 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1462937209-6032-5-git-send-email-cphlipot0@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo

perf script: Fix callchain addresses in db-export

2016-05-11T15:24:58+00:00

Remove the call to map_ip() to adjust al.addr, because it has already
been called when assembling the callchain, in:

  thread__resolve_callchain_sample(perf_sample)
      add_callchain_ip(ip = perf_sample->callchain->ips[j])
          thread__find_addr_location(addr = ip)
              thread__find_addr_map(addr) {
                  al->addr = addr
                  if (al->map)
                      al->addr = al->map->map_ip(al->map, al->addr);
              }

Calling it a second time can result in incorrect addresses being used.
This can have effects such as duplicate symbols being created and
exported.

Signed-off-by: Chris Phlipot 
Cc: Adrian Hunter 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1462937209-6032-4-git-send-email-cphlipot0@gmail.com
[ Show the callchain where it is done, to help reviewing this change down the line ]
Signed-off-by: Arnaldo Carvalho de Melo

perf script: Fix symbol insertion behavior in db-export

2016-05-11T15:24:57+00:00

Use the dso__insert_symbol function instead of symbols__insert() in
order to properly update the dso symbol cache.

If the cache is not updated, then duplicate symbols can be
unintentionally created, inserted, and exported.

This change prevents duplicate symbols from being exported due to
dso__find_symbol() using a stale symbol cache.

Signed-off-by: Chris Phlipot 
Cc: Adrian Hunter 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1462937209-6032-3-git-send-email-cphlipot0@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo

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

2016-05-06T16:00:53+00:00

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 
Acked-by: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1461831551-12213-5-git-send-email-cphlipot0@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo

perf script: Enable db export to output sampled callchains

2016-05-06T16:00:52+00:00

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 
Acked-by: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Peter Zijlstra 
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