Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf updates from Ingo Molnar:
 "Kernel side changes:

   - Improve accuracy of perf/sched clock on x86.  (Adrian Hunter)

   - Intel DS and BTS updates.  (Alexander Shishkin)

   - Intel cstate PMU support.  (Kan Liang)

   - Add group read support to perf_event_read().  (Peter Zijlstra)

   - Branch call hardware sampling support, implemented on x86 and
     PowerPC.  (Stephane Eranian)

   - Event groups transactional interface enhancements.  (Sukadev
     Bhattiprolu)

   - Enable proper x86/intel/uncore PMU support on multi-segment PCI
     systems.  (Taku Izumi)

   - ... misc fixes and cleanups.

  The perf tooling team was very busy again with 200+ commits, the full
  diff doesn't fit into lkml size limits.  Here's an (incomplete) list
  of the tooling highlights:

  New features:

   - Change the default event used in all tools (record/top): use the
     most precise "cycles" hw counter available, i.e. when the user
     doesn't specify any event, it will try using cycles:ppp, cycles:pp,
     etc and fall back transparently until it finds a working counter.
     (Arnaldo Carvalho de Melo)

   - Integration of perf with eBPF that, given an eBPF .c source file
     (or .o file built for the 'bpf' target with clang), will get it
     automatically built, validated and loaded into the kernel via the
     sys_bpf syscall, which can then be used and seen using 'perf trace'
     and other tools.

     (Wang Nan)

  Various user interface improvements:

   - Automatic pager invocation on long help output.  (Namhyung Kim)

   - Search for more options when passing args to -h, e.g.: (Arnaldo
     Carvalho de Melo)

        $ perf report -h interface

        Usage: perf report [<options>]

         --gtk    Use the GTK2 interface
         --stdio  Use the stdio interface
         --tui    Use the TUI interface

   - Show ordered command line options when -h is used or when an
     unknown option is specified.  (Arnaldo Carvalho de Melo)

   - If options are passed after -h, show just its descriptions, not all
     options.  (Arnaldo Carvalho de Melo)

   - Implement column based horizontal scrolling in the hists browser
     (top, report), making it possible to use the TUI for things like
     'perf mem report' where there are many more columns than can fit in
     a terminal.  (Arnaldo Carvalho de Melo)

   - Enhance the error reporting of tracepoint event parsing, e.g.:

       $ oldperf record -e sched:sched_switc usleep 1
       event syntax error: 'sched:sched_switc'
                            \___ unknown tracepoint
       Run 'perf list' for a list of valid events

     Now we get the much nicer:

       $ perf record -e sched:sched_switc ls
       event syntax error: 'sched:sched_switc'
                            \___ can't access trace events

       Error: No permissions to read /sys/kernel/debug/tracing/events/sched/sched_switc
       Hint:  Try 'sudo mount -o remount,mode=755 /sys/kernel/debug'

     And after we have those mount point permissions fixed:

       $ perf record -e sched:sched_switc ls
       event syntax error: 'sched:sched_switc'
                            \___ unknown tracepoint

       Error: File /sys/kernel/debug/tracing/events/sched/sched_switc not found.
       Hint:  Perhaps this kernel misses some CONFIG_ setting to enable this feature?.

     I.e.  basically now the event parsing routing uses the strerror_open()
     routines introduced by and used in 'perf trace' work.  (Jiri Olsa)

   - Fail properly when pattern matching fails to find a tracepoint,
     i.e. '-e non:existent' was being correctly handled, with a proper
     error message about that not being a valid event, but '-e
     non:existent*' wasn't, fix it.  (Jiri Olsa)

   - Do event name substring search as last resort in 'perf list'.
     (Arnaldo Carvalho de Melo)

     E.g.:

       # perf list clock

       List of pre-defined events (to be used in -e):

        cpu-clock                                          [Software event]
        task-clock                                         [Software event]

        uncore_cbox_0/clockticks/                          [Kernel PMU event]
        uncore_cbox_1/clockticks/                          [Kernel PMU event]

        kvm:kvm_pvclock_update                             [Tracepoint event]
        kvm:kvm_update_master_clock                        [Tracepoint event]
        power:clock_disable                                [Tracepoint event]
        power:clock_enable                                 [Tracepoint event]
        power:clock_set_rate                               [Tracepoint event]
        syscalls:sys_enter_clock_adjtime                   [Tracepoint event]
        syscalls:sys_enter_clock_getres                    [Tracepoint event]
        syscalls:sys_enter_clock_gettime                   [Tracepoint event]
        syscalls:sys_enter_clock_nanosleep                 [Tracepoint event]
        syscalls:sys_enter_clock_settime                   [Tracepoint event]
        syscalls:sys_exit_clock_adjtime                    [Tracepoint event]
        syscalls:sys_exit_clock_getres                     [Tracepoint event]
        syscalls:sys_exit_clock_gettime                    [Tracepoint event]
        syscalls:sys_exit_clock_nanosleep                  [Tracepoint event]
        syscalls:sys_exit_clock_settime                    [Tracepoint event]

  Intel PT hardware tracing enhancements:

   - Accept a zero --itrace period, meaning "as often as possible".  In
     the case of Intel PT that is the same as a period of 1 and a unit
     of 'instructions' (i.e.  --itrace=i1i).  (Adrian Hunter)

   - Harmonize itrace's synthesized callchains with the existing
     --max-stack tool option.  (Adrian Hunter)

   - Allow time to be displayed in nanoseconds in 'perf script'.
     (Adrian Hunter)

   - Fix potential infinite loop when handling Intel PT timestamps.
     (Adrian Hunter)

   - Slighly improve Intel PT debug logging.  (Adrian Hunter)

   - Warn when AUX data has been lost, just like when processing
     PERF_RECORD_LOST.  (Adrian Hunter)

   - Further document export-to-postgresql.py script.  (Adrian Hunter)

   - Add option to synthesize branch stack from auxtrace data.  (Adrian
     Hunter)

  Misc notable changes:

   - Switch the default callchain output mode to 'graph,0.5,caller', to
     make it look like the default for other tools, reducing the
     learning curve for people used to 'caller' based viewing.  (Arnaldo
     Carvalho de Melo)

   - various call chain usability enhancements.  (Namhyung Kim)

   - Introduce the 'P' event modifier, meaning 'max precision level,
     please', i.e.:

        $ perf record -e cycles:P usleep 1

     Is now similar to:

        $ perf record usleep 1

     Useful, for instance, when specifying multiple events.  (Jiri Olsa)

   - Add 'socket' sort entry, to sort by the processor socket in 'perf
     top' and 'perf report'.  (Kan Liang)

   - Introduce --socket-filter to 'perf report', for filtering by
     processor socket.  (Kan Liang)

   - Add new "Zoom into Processor Socket" operation in the perf hists
     browser, used in 'perf top' and 'perf report'.  (Kan Liang)

   - Allow probing on kmodules without DWARF.  (Masami Hiramatsu)

   - Fix 'perf probe -l' for probes added to kernel module functions.
     (Masami Hiramatsu)

   - Preparatory work for the 'perf stat record' feature that will allow
     generating perf.data files with counting data in addition to the
     sampling mode we have now (Jiri Olsa)

   - Update libtraceevent KVM plugin.  (Paolo Bonzini)

   - ... plus lots of other enhancements that I failed to list properly,
     by: Adrian Hunter, Alexander Shishkin, Andi Kleen, Andrzej Hajda,
     Arnaldo Carvalho de Melo, Dima Kogan, Don Zickus, Geliang Tang, He
     Kuang, Huaitong Han, Ingo Molnar, Jan Stancek, Jiri Olsa, Kan
     Liang, Kirill Tkhai, Masami Hiramatsu, Matt Fleming, Namhyung Kim,
     Paolo Bonzini, Peter Zijlstra, Rabin Vincent, Scott Wood, Stephane
     Eranian, Sukadev Bhattiprolu, Taku Izumi, Vaishali Thakkar, Wang
     Nan, Yang Shi and Yunlong Song"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (260 commits)
  perf unwind: Pass symbol source to libunwind
  tools build: Fix libiberty feature detection
  perf tools: Compile scriptlets to BPF objects when passing '.c' to --event
  perf record: Add clang options for compiling BPF scripts
  perf bpf: Attach eBPF filter to perf event
  perf tools: Make sure fixdep is built before libbpf
  perf script: Enable printing of branch stack
  perf trace: Add cmd string table to decode sys_bpf first arg
  perf bpf: Collect perf_evsel in BPF object files
  perf tools: Load eBPF object into kernel
  perf tools: Create probe points for BPF programs
  perf tools: Enable passing bpf object file to --event
  perf ebpf: Add the libbpf glue
  perf tools: Make perf depend on libbpf
  perf symbols: Fix endless loop in dso__split_kallsyms_for_kcore
  perf tools: Enable pre-event inherit setting by config terms
  perf symbols: we can now read separate debug-info files based on a build ID
  perf symbols: Fix type error when reading a build-id
  perf tools: Search for more options when passing args to -h
  perf stat: Cache aggregated map entries in extra cpumap
  ...

1 files changed, 103 insertions, 17 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 092a0e8a479a..d841d33bcdc9 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -140,33 +140,67 @@ struct hw_perf_event {
 		};
 #endif
 	};
+	/*
+	 * If the event is a per task event, this will point to the task in
+	 * question. See the comment in perf_event_alloc().
+	 */
 	struct task_struct		*target;
+
+/*
+ * hw_perf_event::state flags; used to track the PERF_EF_* state.
+ */
+#define PERF_HES_STOPPED	0x01 /* the counter is stopped */
+#define PERF_HES_UPTODATE	0x02 /* event->count up-to-date */
+#define PERF_HES_ARCH		0x04
+
 	int				state;
+
+	/*
+	 * The last observed hardware counter value, updated with a
+	 * local64_cmpxchg() such that pmu::read() can be called nested.
+	 */
 	local64_t			prev_count;
+
+	/*
+	 * The period to start the next sample with.
+	 */
 	u64				sample_period;
+
+	/*
+	 * The period we started this sample with.
+	 */
 	u64				last_period;
+
+	/*
+	 * However much is left of the current period; note that this is
+	 * a full 64bit value and allows for generation of periods longer
+	 * than hardware might allow.
+	 */
 	local64_t			period_left;
+
+	/*
+	 * State for throttling the event, see __perf_event_overflow() and
+	 * perf_adjust_freq_unthr_context().
+	 */
 	u64                             interrupts_seq;
 	u64				interrupts;
 
+	/*
+	 * State for freq target events, see __perf_event_overflow() and
+	 * perf_adjust_freq_unthr_context().
+	 */
 	u64				freq_time_stamp;
 	u64				freq_count_stamp;
 #endif
 };
 
-/*
- * hw_perf_event::state flags
- */
-#define PERF_HES_STOPPED	0x01 /* the counter is stopped */
-#define PERF_HES_UPTODATE	0x02 /* event->count up-to-date */
-#define PERF_HES_ARCH		0x04
-
 struct perf_event;
 
 /*
  * Common implementation detail of pmu::{start,commit,cancel}_txn
  */
-#define PERF_EVENT_TXN 0x1
+#define PERF_PMU_TXN_ADD  0x1		/* txn to add/schedule event on PMU */
+#define PERF_PMU_TXN_READ 0x2		/* txn to read event group from PMU */
 
 /**
  * pmu::capabilities flags
@@ -210,7 +244,19 @@ struct pmu {
 
 	/*
 	 * Try and initialize the event for this PMU.
-	 * Should return -ENOENT when the @event doesn't match this PMU.
+	 *
+	 * Returns:
+	 *  -ENOENT	-- @event is not for this PMU
+	 *
+	 *  -ENODEV	-- @event is for this PMU but PMU not present
+	 *  -EBUSY	-- @event is for this PMU but PMU temporarily unavailable
+	 *  -EINVAL	-- @event is for this PMU but @event is not valid
+	 *  -EOPNOTSUPP -- @event is for this PMU, @event is valid, but not supported
+	 *  -EACCESS	-- @event is for this PMU, @event is valid, but no privilidges
+	 *
+	 *  0		-- @event is for this PMU and valid
+	 *
+	 * Other error return values are allowed.
 	 */
 	int (*event_init)		(struct perf_event *event);
 
@@ -221,27 +267,61 @@ struct pmu {
 	void (*event_mapped)		(struct perf_event *event); /*optional*/
 	void (*event_unmapped)		(struct perf_event *event); /*optional*/
 
+	/*
+	 * Flags for ->add()/->del()/ ->start()/->stop(). There are
+	 * matching hw_perf_event::state flags.
+	 */
 #define PERF_EF_START	0x01		/* start the counter when adding    */
 #define PERF_EF_RELOAD	0x02		/* reload the counter when starting */
 #define PERF_EF_UPDATE	0x04		/* update the counter when stopping */
 
 	/*
-	 * Adds/Removes a counter to/from the PMU, can be done inside
-	 * a transaction, see the ->*_txn() methods.
+	 * Adds/Removes a counter to/from the PMU, can be done inside a
+	 * transaction, see the ->*_txn() methods.
+	 *
+	 * The add/del callbacks will reserve all hardware resources required
+	 * to service the event, this includes any counter constraint
+	 * scheduling etc.
+	 *
+	 * Called with IRQs disabled and the PMU disabled on the CPU the event
+	 * is on.
+	 *
+	 * ->add() called without PERF_EF_START should result in the same state
+	 *  as ->add() followed by ->stop().
+	 *
+	 * ->del() must always PERF_EF_UPDATE stop an event. If it calls
+	 *  ->stop() that must deal with already being stopped without
+	 *  PERF_EF_UPDATE.
 	 */
 	int  (*add)			(struct perf_event *event, int flags);
 	void (*del)			(struct perf_event *event, int flags);
 
 	/*
-	 * Starts/Stops a counter present on the PMU. The PMI handler
-	 * should stop the counter when perf_event_overflow() returns
-	 * !0. ->start() will be used to continue.
+	 * Starts/Stops a counter present on the PMU.
+	 *
+	 * The PMI handler should stop the counter when perf_event_overflow()
+	 * returns !0. ->start() will be used to continue.
+	 *
+	 * Also used to change the sample period.
+	 *
+	 * Called with IRQs disabled and the PMU disabled on the CPU the event
+	 * is on -- will be called from NMI context with the PMU generates
+	 * NMIs.
+	 *
+	 * ->stop() with PERF_EF_UPDATE will read the counter and update
+	 *  period/count values like ->read() would.
+	 *
+	 * ->start() with PERF_EF_RELOAD will reprogram the the counter
+	 *  value, must be preceded by a ->stop() with PERF_EF_UPDATE.
 	 */
 	void (*start)			(struct perf_event *event, int flags);
 	void (*stop)			(struct perf_event *event, int flags);
 
 	/*
 	 * Updates the counter value of the event.
+	 *
+	 * For sampling capable PMUs this will also update the software period
+	 * hw_perf_event::period_left field.
 	 */
 	void (*read)			(struct perf_event *event);
 
@@ -252,20 +332,26 @@ struct pmu {
 	 *
 	 * Start the transaction, after this ->add() doesn't need to
 	 * do schedulability tests.
+	 *
+	 * Optional.
 	 */
-	void (*start_txn)		(struct pmu *pmu); /* optional */
+	void (*start_txn)		(struct pmu *pmu, unsigned int txn_flags);
 	/*
 	 * If ->start_txn() disabled the ->add() schedulability test
 	 * then ->commit_txn() is required to perform one. On success
 	 * the transaction is closed. On error the transaction is kept
 	 * open until ->cancel_txn() is called.
+	 *
+	 * Optional.
 	 */
-	int  (*commit_txn)		(struct pmu *pmu); /* optional */
+	int  (*commit_txn)		(struct pmu *pmu);
 	/*
 	 * Will cancel the transaction, assumes ->del() is called
 	 * for each successful ->add() during the transaction.
+	 *
+	 * Optional.
 	 */
-	void (*cancel_txn)		(struct pmu *pmu); /* optional */
+	void (*cancel_txn)		(struct pmu *pmu);
 
 	/*
 	 * Will return the value for perf_event_mmap_page::index for this event,