perf tests: Add dlfilter test

Add a perf test to test the dlfilter C API.

A perf.data file is synthesized and then processed by perf script with a
dlfilter named dlfilter-test-api-v0.so. Also a C file is compiled to
provide a dso to match the synthesized perf.data file.

Committer testing:

[root@five ~]# perf test dlfilter
72: dlfilter C API : Ok
[root@five ~]# perf test -v dlfilter
72: dlfilter C API :
--- start ---
test child forked, pid 3387712
Checking for gcc
Command: gcc --version
gcc (GCC) 11.1.1 20210531 (Red Hat 11.1.1-3)
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

dlfilters path: /var/home/acme/libexec/perf-core/dlfilters
Command: gcc -g -o /tmp/dlfilter-test-3387712-prog /tmp/dlfilter-test-3387712-prog.c
Creating new host machine structure
Command: /var/home/acme/bin/perf script -i /tmp/dlfilter-test-3387712-perf-data --dlfilter /var/home/acme/libexec/perf-core/dlfilters/dlfilter-test-api-v0.so --dlarg first --dlarg 1 --dlarg 4198669 --dlarg 4198662 --dlarg 0 --dlarg last
start API
filter_event_early API
filter_event API
stop API
Command: /var/home/acme/bin/perf script -i /tmp/dlfilter-test-3387712-perf-data --dlfilter /var/home/acme/libexec/perf-core/dlfilters/dlfilter-test-api-v0.so --dlarg first --dlarg 1 --dlarg 4198669 --dlarg 4198662 --dlarg 1 --dlarg last
start API
filter_event_early API
filter_event API
stop API
Command: /var/home/acme/bin/perf script -i /tmp/dlfilter-test-3387712-perf-data --dlfilter /var/home/acme/libexec/perf-core/dlfilters/dlfilter-test-api-v0.so --dlarg first --dlarg 1 --dlarg 4198669 --dlarg 4198662 --dlarg 2 --dlarg last
start API
filter_event_early API
stop API
test child finished with 0
---- end ----
dlfilter C API: Ok
[root@five ~]#

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: https //lore.kernel.org/r/20210811101036.17986-7-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf script: Add option to pass arguments to dlfilters

Add option --dlarg to pass arguments to dlfilters. The --dlarg option can
be repeated to pass more than 1 argument.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210627131818.810-5-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf script: Add option to list dlfilters

Add option --list-dlfilters to list dlfilters in the current directory or
the exec-path e.g. ~/libexec/perf-core/dlfilters. Use with option -v (must
come before option --list-dlfilters) to show long descriptions.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210627131818.810-4-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf script: Add dlfilter__filter_event_early()

filter_event_early() can be more than 30% faster than filter_event()
because it is called before internal filtering. In other respects it
is the same as filter_event(), except that it will be passed events
that have yet to be filtered out.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210627131818.810-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf script: Add API for filtering via dynamically loaded shared object

In some cases, users want to filter very large amounts of data (e.g.
from AUX area tracing like Intel PT) looking for something specific.
While scripting such as Python can be used, Python is 10 to 20 times
slower than C. So define a C API so that custom filters can be written
and loaded.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210627131818.810-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>