Commit d1ee8bc1 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

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

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

  - Add support for using several Intel PT features (CYC, MTC packets), the
    relevant documentation was updated: tools/perf/Documentation/intel-pt.txt,
    briefly describing those packets, its purposes, how to configure them in
    the event config terms and relevant external documentation for further
    reading. (Adrian Hunter)

  - Introduce support for probing at an absolute address, for user and kernel
    'perf probe's, useful when one have the symbol maps on a developer machine
    but not on an embedded system. (Wang Nan)

  - Fix 'perf probe' list results when a symbol can't be found or the
    address is zero and when an offset is provided without a function (Wang Nan)

  - Do not print '0x (null)' in uprobes when offset is zero (Wang Nan)

  - Clear the progress bar at the end of a ordered_events flush, fixing
    an UI artifact when, after ordering the events the screen doesn't get
    completely redraw, for instance, when an error window covers just the
    center of the screen and waits for user input. (Arnaldo Carvalho de Melo)

  - Fix 'annotate' segfault by resetting the dso find_symbol cache when removing
    symbols. (Arnaldo Carvalho de Melo)

Infrastructure changes:

  - Allow duplicate objects in the object list, just like it is possible to have
    things like this, in the kernel:

      drivers/Makefile:obj-$(CONFIG_PCI)        += usb/
      drivers/Makefile:obj-$(CONFIG_USB_GADGET) += usb/

    (Jiri Olsa)

  - Fix Intel PT 'instructions' sample period. (Adrian Hunter)

  - Prevent segfault when reading probe point with absolute address. (Wang Nan)

Build fixes:

  - Fix tarball build broken by pt/bts. (Adrian Hunter)

  - Remove export.h from MANIFEST, fixing the perf tarball make target. (Jiri Olsa)

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents 0e53909a a2fb3382

kernel/trace/trace_uprobe.c

+16 −1
Original line number Diff line number Diff line
@@ -601,7 +601,22 @@ static int probes_seq_show(struct seq_file *m, void *v) 


	seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system,

			trace_event_name(&tu->tp.call));

	seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset);

	seq_printf(m, " %s:", tu->filename);



	/* Don't print "0x  (null)" when offset is 0 */

	if (tu->offset) {

		seq_printf(m, "0x%p", (void *)tu->offset);

	} else {

		switch (sizeof(void *)) {

		case 4:

			seq_printf(m, "0x00000000");

			break;

		case 8:

		default:

			seq_printf(m, "0x0000000000000000");

			break;

		}

	}



	for (i = 0; i < tu->tp.nr_args; i++)

		seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);

tools/build/Documentation/Build.txt

+1 −0
Original line number Diff line number Diff line
@@ -66,6 +66,7 @@ To follow the above example, the user provides following 'Build' files: 
  ex/Build:

    ex-y += a.o

    ex-y += b.o

    ex-y += b.o # duplicates in the lists are allowed



    libex-y += c.o

    libex-y += d.o

tools/build/Makefile.build

+1 −1
Original line number Diff line number Diff line
@@ -63,7 +63,7 @@ quiet_cmd_gen = GEN $@ 
# If there's nothing to link, create empty $@ object.

quiet_cmd_ld_multi = LD       $@

      cmd_ld_multi = $(if $(strip $(obj-y)),\

		       $(LD) -r -o $@ $(obj-y),rm -f $@; $(AR) rcs $@)

		       $(LD) -r -o $@  $(filter $(obj-y),$^),rm -f $@; $(AR) rcs $@)



# Build rules

$(OUTPUT)%.o: %.c FORCE

tools/build/tests/ex/Build

+1 −0
Original line number Diff line number Diff line 
ex-y += ex.o

ex-y += a.o

ex-y += b.o

ex-y += b.o

ex-y += empty/

ex-y += empty2/

tools/perf/Documentation/intel-pt.txt

+186 −8
Original line number Diff line number Diff line
@@ -142,19 +142,21 @@ which is the same as 


	-e intel_pt/tsc=1,noretcomp=0/



Note there are now new config terms - see section 'config terms' further below.



The config terms are listed in /sys/devices/intel_pt/format.  They are bit

fields within the config member of the struct perf_event_attr which is

passed to the kernel by the perf_event_open system call.  They correspond to bit

fields in the IA32_RTIT_CTL MSR.  Here is a list of them and their definitions:



	$ for f in `ls /sys/devices/intel_pt/format`;do

	> echo $f

	> cat /sys/devices/intel_pt/format/$f

	> done

	noretcomp

	config:11

	tsc

	config:10

	$ grep -H . /sys/bus/event_source/devices/intel_pt/format/*

	/sys/bus/event_source/devices/intel_pt/format/cyc:config:1

	/sys/bus/event_source/devices/intel_pt/format/cyc_thresh:config:19-22

	/sys/bus/event_source/devices/intel_pt/format/mtc:config:9

	/sys/bus/event_source/devices/intel_pt/format/mtc_period:config:14-17

	/sys/bus/event_source/devices/intel_pt/format/noretcomp:config:11

	/sys/bus/event_source/devices/intel_pt/format/psb_period:config:24-27

	/sys/bus/event_source/devices/intel_pt/format/tsc:config:10



Note that the default config must be overridden for each term i.e.
@@ -209,9 +211,185 @@ perf_event_attr is displayed if the -vv option is used e.g. 
	------------------------------------------------------------





config terms

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



The June 2015 version of Intel 64 and IA-32 Architectures Software Developer

Manuals, Chapter 36 Intel Processor Trace, defined new Intel PT features.

Some of the features are reflect in new config terms.  All the config terms are

described below.



tsc		Always supported.  Produces TSC timestamp packets to provide

		timing information.  In some cases it is possible to decode

		without timing information, for example a per-thread context

		that does not overlap executable memory maps.



		The default config selects tsc (i.e. tsc=1).



noretcomp	Always supported.  Disables "return compression" so a TIP packet

		is produced when a function returns.  Causes more packets to be

		produced but might make decoding more reliable.



		The default config does not select noretcomp (i.e. noretcomp=0).



psb_period	Allows the frequency of PSB packets to be specified.



		The PSB packet is a synchronization packet that provides a

		starting point for decoding or recovery from errors.



		Support for psb_period is indicated by:



			/sys/bus/event_source/devices/intel_pt/caps/psb_cyc



		which contains "1" if the feature is supported and "0"

		otherwise.



		Valid values are given by:



			/sys/bus/event_source/devices/intel_pt/caps/psb_periods



		which contains a hexadecimal value, the bits of which represent

		valid values e.g. bit 2 set means value 2 is valid.



		The psb_period value is converted to the approximate number of

		trace bytes between PSB packets as:



			2 ^ (value + 11)



		e.g. value 3 means 16KiB bytes between PSBs



		If an invalid value is entered, the error message

		will give a list of valid values e.g.



			$ perf record -e intel_pt/psb_period=15/u uname

			Invalid psb_period for intel_pt. Valid values are: 0-5



		If MTC packets are selected, the default config selects a value

		of 3 (i.e. psb_period=3) or the nearest lower value that is

		supported (0 is always supported).  Otherwise the default is 0.



		If decoding is expected to be reliable and the buffer is large

		then a large PSB period can be used.



		Because a TSC packet is produced with PSB, the PSB period can

		also affect the granularity to timing information in the absence

		of MTC or CYC.



mtc		Produces MTC timing packets.



		MTC packets provide finer grain timestamp information than TSC

		packets.  MTC packets record time using the hardware crystal

		clock (CTC) which is related to TSC packets using a TMA packet.



		Support for this feature is indicated by:



			/sys/bus/event_source/devices/intel_pt/caps/mtc



		which contains "1" if the feature is supported and

		"0" otherwise.



		The frequency of MTC packets can also be specified - see

		mtc_period below.



mtc_period	Specifies how frequently MTC packets are produced - see mtc

		above for how to determine if MTC packets are supported.



		Valid values are given by:



			/sys/bus/event_source/devices/intel_pt/caps/mtc_periods



		which contains a hexadecimal value, the bits of which represent

		valid values e.g. bit 2 set means value 2 is valid.



		The mtc_period value is converted to the MTC frequency as:



			CTC-frequency / (2 ^ value)



		e.g. value 3 means one eighth of CTC-frequency



		Where CTC is the hardware crystal clock, the frequency of which

		can be related to TSC via values provided in cpuid leaf 0x15.



		If an invalid value is entered, the error message

		will give a list of valid values e.g.



			$ perf record -e intel_pt/mtc_period=15/u uname

			Invalid mtc_period for intel_pt. Valid values are: 0,3,6,9



		The default value is 3 or the nearest lower value

		that is supported (0 is always supported).



cyc		Produces CYC timing packets.



		CYC packets provide even finer grain timestamp information than

		MTC and TSC packets.  A CYC packet contains the number of CPU

		cycles since the last CYC packet. Unlike MTC and TSC packets,

		CYC packets are only sent when another packet is also sent.



		Support for this feature is indicated by:



			/sys/bus/event_source/devices/intel_pt/caps/psb_cyc



		which contains "1" if the feature is supported and

		"0" otherwise.



		The number of CYC packets produced can be reduced by specifying

		a threshold - see cyc_thresh below.



cyc_thresh	Specifies how frequently CYC packets are produced - see cyc

		above for how to determine if CYC packets are supported.



		Valid cyc_thresh values are given by:



			/sys/bus/event_source/devices/intel_pt/caps/cycle_thresholds



		which contains a hexadecimal value, the bits of which represent

		valid values e.g. bit 2 set means value 2 is valid.



		The cyc_thresh value represents the minimum number of CPU cycles

		that must have passed before a CYC packet can be sent.  The

		number of CPU cycles is:



			2 ^ (value - 1)



		e.g. value 4 means 8 CPU cycles must pass before a CYC packet

		can be sent.  Note a CYC packet is still only sent when another

		packet is sent, not at, e.g. every 8 CPU cycles.



		If an invalid value is entered, the error message

		will give a list of valid values e.g.



			$ perf record -e intel_pt/cyc,cyc_thresh=15/u uname

			Invalid cyc_thresh for intel_pt. Valid values are: 0-12



		CYC packets are not requested by default.



no_force_psb	This is a driver option and is not in the IA32_RTIT_CTL MSR.



		It stops the driver resetting the byte count to zero whenever

		enabling the trace (for example on context switches) which in

		turn results in no PSB being forced.  However some processors

		will produce a PSB anyway.



		In any case, there is still a PSB when the trace is enabled for

		the first time.



		no_force_psb can be used to slightly decrease the trace size but

		may make it harder for the decoder to recover from errors.



		no_force_psb is not selected by default.





new snapshot option

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



The difference between full trace and snapshot from the kernel's perspective is

that in full trace we don't overwrite trace data that the user hasn't collected

yet (and indicated that by advancing aux_tail), whereas in snapshot mode we let

the trace run and overwrite older data in the buffer so that whenever something

interesting happens, we can stop it and grab a snapshot of what was going on

around that interesting moment.



To select snapshot mode a new option has been added:



	-S

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