linux-stable.git/tools/perf/Documentation, branch linux-5.14.y

perf intel-pt: Add a config for max loops without consuming a packet

2021-07-07T14:40:56+00:00

The Intel PT decoder limits the number of unconditional branches (e.g.
jmps) decoded without consuming any trace packets. Generally, a loop
needs a conditional branch which generates a TNT packet, whereas a "ret"
instruction will generate a TIP or TNT packet. So exceeding the limit is
assumed to be a never-ending loop, which can happen if there has been a
decoding error putting the decoder at the wrong place in the code.

Up until now, the limit of 10000 has been enough but some analytic
purposes have been reported to exceed that.

Increase the limit to 100000, and make it configurable via perf config
intel-pt.max-loops. Also amend the "Never-ending loop" message to
mention the configuration entry.

Signed-off-by: Adrian Hunter 
Reviewed-by: Andi Kleen 
Cc: Jiri Olsa 
Link: http://lore.kernel.org/lkml/20210701175132.3977-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf dlfilter: Add object_code() to perf_dlfilter_fns

2021-07-01T19:14:38+00:00

Add a function, for use by dlfilters, to read object code.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20210627131818.810-11-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf dlfilter: Add attr() to perf_dlfilter_fns

2021-07-01T19:14:38+00:00

Add a function, for use by dlfilters, to return the perf_event_attr
structure.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20210627131818.810-10-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf dlfilter: Add srcline() to perf_dlfilter_fns

2021-07-01T19:14:38+00:00

Add a function, for use by dlfilters, to return source code file name and
line number.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20210627131818.810-9-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf dlfilter: Add insn() to perf_dlfilter_fns

2021-07-01T19:14:38+00:00

Add a function, for use by dlfilters, to return instruction bytes.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20210627131818.810-8-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf dlfilter: Add resolve_address() to perf_dlfilter_fns

2021-07-01T19:14:38+00:00

Add a function, for use by dlfilters, to resolve addresses from branch
stacks or callchains.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20210627131818.810-7-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf script: Add option to pass arguments to dlfilters

2021-07-01T19:14:37+00:00

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 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20210627131818.810-5-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf script: Add option to list dlfilters

2021-07-01T19:14:37+00:00

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 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20210627131818.810-4-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf script: Add dlfilter__filter_event_early()

2021-07-01T19:14:37+00:00

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 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20210627131818.810-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

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

2021-07-01T19:14:37+00:00

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 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20210627131818.810-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo