Commit aeaae7d6 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Merge tag 'perf-core-for-mingo-20160408' of... 

Merge tag 'perf-core-for-mingo-20160408' 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:

- Beautify more syscall arguments in 'perf trace', using the type column in
  tracepoint /format fields to attach, for instance, a pid_t resolver to the
  thread COMM, also attach a mode_t beautifier in the same fashion
  (Arnaldo Carvalho de Melo)

- Build the syscall table id <-> name resolver using the same .tbl file
  used in the kernel to generate headers, to avoid the delay in getting
  new syscalls supported in the audit-libs external dependency, done so
  far only for x86_64 (Arnaldo Carvalho de Melo)

- Improve the documentation of event specifications (Andi Kleen)

- Process update events in 'perf script', fixing up this use case:

    # perf stat -a -I 1000 -e cycles record | perf script -s script.py

- Shared object symbol adjustment fixes, fixing symbol resolution in
  Android (Wang Nan)

Infrastructure changes:

- Add dedicated unwind addr_space member into thread struct, to allow
  tools to use thread->priv, noticed while working on having callchains
  in 'perf trace' (Jiri Olsa)

Build fixes:

- Fix the build in Ubuntu 12.04 (Arnaldo Carvalho de Melo, Vinson Lee)

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents 889fac6d 99e87f7b

tools/build/Makefile.feature

+2 −0
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ endef 
FEATURE_TESTS_BASIC :=			\

	backtrace			\

	dwarf				\

	dwarf_getlocations		\

	fortify-source			\

	sync-compare-and-swap		\

	glibc				\
@@ -78,6 +79,7 @@ endif 


FEATURE_DISPLAY ?=			\

	dwarf				\

	dwarf_getlocations		\

	glibc				\

	gtk2				\

	libaudit			\

tools/build/feature/Makefile

+4 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ FILES= \ 
	test-backtrace.bin		\

	test-bionic.bin			\

	test-dwarf.bin			\

	test-dwarf_getlocations.bin	\

	test-fortify-source.bin		\

	test-sync-compare-and-swap.bin	\

	test-glibc.bin			\
@@ -82,6 +83,9 @@ endif 
$(OUTPUT)test-dwarf.bin:

	$(BUILD) $(DWARFLIBS)



$(OUTPUT)test-dwarf_getlocations.bin:

	$(BUILD) $(DWARFLIBS)



$(OUTPUT)test-libelf-mmap.bin:

	$(BUILD) -lelf

tools/build/feature/test-all.c

+5 −0
Original line number Diff line number Diff line
@@ -41,6 +41,10 @@ 
# include "test-dwarf.c"

#undef main



#define main main_test_dwarf_getlocations

# include "test-dwarf_getlocations.c"

#undef main



#define main main_test_libelf_getphdrnum

# include "test-libelf-getphdrnum.c"

#undef main
@@ -143,6 +147,7 @@ int main(int argc, char *argv[]) 
	main_test_libelf_mmap();

	main_test_glibc();

	main_test_dwarf();

	main_test_dwarf_getlocations();

	main_test_libelf_getphdrnum();

	main_test_libunwind();

	main_test_libaudit();

tools/build/feature/test-dwarf_getlocations.c

0 → 100644
+12 −0
Original line number Diff line number Diff line 
#include <stdlib.h>

#include <elfutils/libdw.h>



int main(void)

{

	Dwarf_Addr base, start, end;

	Dwarf_Attribute attr;

	Dwarf_Op *op;

        size_t nops;

	ptrdiff_t offset = 0;

        return (int)dwarf_getlocations(&attr, offset, &base, &start, &end, &op, &nops);

}

tools/perf/Documentation/perf-list.txt

+106 −1
Original line number Diff line number Diff line
@@ -93,6 +93,67 @@ raw encoding of 0x1A8 can be used: 
You should refer to the processor specific documentation for getting these

details. Some of them are referenced in the SEE ALSO section below.



ARBITRARY PMUS

--------------



perf also supports an extended syntax for specifying raw parameters

to PMUs. Using this typically requires looking up the specific event

in the CPU vendor specific documentation.



The available PMUs and their raw parameters can be listed with



  ls /sys/devices/*/format



For example the raw event "LSD.UOPS" core pmu event above could

be specified as



  perf stat -e cpu/event=0xa8,umask=0x1,name=LSD.UOPS_CYCLES,cmask=1/ ...



PER SOCKET PMUS

---------------



Some PMUs are not associated with a core, but with a whole CPU socket.

Events on these PMUs generally cannot be sampled, but only counted globally

with perf stat -a. They can be bound to one logical CPU, but will measure

all the CPUs in the same socket.



This example measures memory bandwidth every second

on the first memory controller on socket 0 of a Intel Xeon system



  perf stat -C 0 -a uncore_imc_0/cas_count_read/,uncore_imc_0/cas_count_write/ -I 1000 ...



Each memory controller has its own PMU.  Measuring the complete system

bandwidth would require specifying all imc PMUs (see perf list output),

and adding the values together.



This example measures the combined core power every second



  perf stat -I 1000 -e power/energy-cores/  -a



ACCESS RESTRICTIONS

-------------------



For non root users generally only context switched PMU events are available.

This is normally only the events in the cpu PMU, the predefined events

like cycles and instructions and some software events.



Other PMUs and global measurements are normally root only.

Some event qualifiers, such as "any", are also root only.



This can be overriden by setting the kernel.perf_event_paranoid

sysctl to -1, which allows non root to use these events.



For accessing trace point events perf needs to have read access to

/sys/kernel/debug/tracing, even when perf_event_paranoid is in a relaxed

setting.



TRACING

-------



Some PMUs control advanced hardware tracing capabilities, such as Intel PT,

that allows low overhead execution tracing.  These are described in a separate

intel-pt.txt document.



PARAMETERIZED EVENTS

--------------------
@@ -106,6 +167,50 @@ also be supplied. For example: 


  perf stat -C 0 -e 'hv_gpci/dtbp_ptitc,phys_processor_idx=0x2/' ...



EVENT GROUPS

------------



Perf supports time based multiplexing of events, when the number of events

active exceeds the number of hardware performance counters. Multiplexing

can cause measurement errors when the workload changes its execution

profile.



When metrics are computed using formulas from event counts, it is useful to

ensure some events are always measured together as a group to minimize multiplexing

errors. Event groups can be specified using { }.



  perf stat -e '{instructions,cycles}' ...



The number of available performance counters depend on the CPU. A group

cannot contain more events than available counters.

For example Intel Core CPUs typically have four generic performance counters

for the core, plus three fixed counters for instructions, cycles and

ref-cycles. Some special events have restrictions on which counter they

can schedule, and may not support multiple instances in a single group.

When too many events are specified in the group none of them will not

be measured.



Globally pinned events can limit the number of counters available for

other groups. On x86 systems, the NMI watchdog pins a counter by default.

The nmi watchdog can be disabled as root with



	echo 0 > /proc/sys/kernel/nmi_watchdog



Events from multiple different PMUs cannot be mixed in a group, with

some exceptions for software events.



LEADER SAMPLING

---------------



perf also supports group leader sampling using the :S specifier.



  perf record -e '{cycles,instructions}:S' ...

  perf report --group



Normally all events in a event group sample, but with :S only

the first event (the leader) samples, and it only reads the values of the

other events in the group.



OPTIONS

-------
@@ -143,5 +248,5 @@ SEE ALSO 
--------

linkperf:perf-stat[1], linkperf:perf-top[1],

linkperf:perf-record[1],

http://www.intel.com/Assets/PDF/manual/253669.pdf[Intel® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide],

http://www.intel.com/sdm/[Intel® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide],

http://support.amd.com/us/Processor_TechDocs/24593_APM_v2.pdf[AMD64 Architecture Programmer’s Manual Volume 2: System Programming]

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