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  1. 16 May, 2019 5 commits
    • Adrian Hunter's avatar
      perf intel-pt: Fix sample timestamp wrt non-taken branches · 1b6599a9
      Adrian Hunter authored 
      The sample timestamp is updated to ensure that the timestamp represents
the time of the sample and not a branch that the decoder is still
walking towards. The sample timestamp is updated when the decoder
returns, but the decoder does not return for non-taken branches. Update
the sample timestamp then also.

Note that commit 3f04d98e ("perf intel-pt: Improve sample
timestamp") was also a stable fix and appears, for example, in v4.4
stable tree as commit a4ebb58f ("perf intel-pt: Improve sample
timestamp").
Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org # v4.4+
Fixes: 3f04d98e ("perf intel-pt: Improve sample timestamp")
Link: http://lkml.kernel.org/r/20190510124143.27054-4-adrian.hunter@intel.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      1b6599a9
    • Adrian Hunter's avatar
      perf intel-pt: Fix improved sample timestamp · 61b6e08d
      Adrian Hunter authored 
      The decoder uses its current timestamp in samples. Usually that is a
timestamp that has already passed, but in some cases it is a timestamp
for a branch that the decoder is walking towards, and consequently
hasn't reached.

The intel_pt_sample_time() function decides which is which, but was not
handling TNT packets exactly correctly.

In the case of TNT, the timestamp applies to the first branch, so the
decoder must first walk to that branch.

That means intel_pt_sample_time() should return true for TNT, and this
patch makes that change. However, if the first branch is a non-taken
branch (i.e. a 'N'), then intel_pt_sample_time() needs to return false
for subsequent taken branches in the same TNT packet.

To handle that, introduce a new state INTEL_PT_STATE_TNT_CONT to
distinguish the cases.

Note that commit 3f04d98e ("perf intel-pt: Improve sample
timestamp") was also a stable fix and appears, for example, in v4.4
stable tree as commit a4ebb58f ("perf intel-pt: Improve sample
timestamp").
Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org # v4.4+
Fixes: 3f04d98e ("perf intel-pt: Improve sample timestamp")
Link: http://lkml.kernel.org/r/20190510124143.27054-3-adrian.hunter@intel.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      61b6e08d
    • Adrian Hunter's avatar
      perf intel-pt: Fix instructions sampling rate · 7ba8fa20
      Adrian Hunter authored 
      The timestamp used to determine if an instruction sample is made, is an
estimate based on the number of instructions since the last known
timestamp. A consequence is that it might go backwards, which results in
extra samples. Change it so that a sample is only made when the
timestamp goes forwards.

Note this does not affect a sampling period of 0 or sampling periods
specified as a count of instructions.

Example:

 Before:

 $ perf script --itrace=i10us
 ls 13812 [003] 2167315.222583:       3270 instructions:u:      7fac71e2e494 __GI___tunables_init+0xf4 (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222667:      30902 instructions:u:      7fac71e2da0f _dl_cache_libcmp+0x2f (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222667:         10 instructions:u:      7fac71e2d9ff _dl_cache_libcmp+0x1f (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222667:          8 instructions:u:      7fac71e2d9ea _dl_cache_libcmp+0xa (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222667:         14 instructions:u:      7fac71e2d9ea _dl_cache_libcmp+0xa (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222667:          6 instructions:u:      7fac71e2d9ff _dl_cache_libcmp+0x1f (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222667:         14 instructions:u:      7fac71e2d9ff _dl_cache_libcmp+0x1f (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222667:          4 instructions:u:      7fac71e2dab2 _dl_cache_libcmp+0xd2 (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222728:      16423 instructions:u:      7fac71e2477a _dl_map_object_deps+0x1ba (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222734:      12731 instructions:u:      7fac71e27938 _dl_name_match_p+0x68 (/lib/x86_64-linux-gnu/ld-2.28.so)
 ...

 After:
 $ perf script --itrace=i10us
 ls 13812 [003] 2167315.222583:       3270 instructions:u:      7fac71e2e494 __GI___tunables_init+0xf4 (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222667:      30902 instructions:u:      7fac71e2da0f _dl_cache_libcmp+0x2f (/lib/x86_64-linux-gnu/ld-2.28.so)
 ls 13812 [003] 2167315.222728:      16479 instructions:u:      7fac71e2477a _dl_map_object_deps+0x1ba (/lib/x86_64-linux-gnu/ld-2.28.so)
 ...
Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Fixes: f4aa0819 ("perf tools: Add Intel PT decoder")
Link: http://lkml.kernel.org/r/20190510124143.27054-2-adrian.hunter@intel.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      7ba8fa20
    • Kan Liang's avatar
      perf regs x86: Add X86 specific arch__intr_reg_mask() · 6466ec14
      Kan Liang authored 
      XMM registers can be collected on Icelake and later platforms.

Add specific arch__intr_reg_mask(), which creating an event to check if
the kernel and hardware can collect XMM registers.

Test on Skylake which doesn't support XMM registers collection. There is
nothing changed.

   #perf record -I?
   available registers: AX BX CX DX SI DI BP SP IP FLAGS CS SS R8 R9
   R10 R11 R12 R13 R14 R15

   Usage: perf record [<options>] [<command>]
    or: perf record [<options>] -- <command> [<options>]

    -I, --intr-regs[=<any register>]
                          sample selected machine registers on
   interrupt, use '-I?' to list register names

   #perf record -I
   [ perf record: Woken up 1 times to write data ]
   [ perf record: Captured and wrote 0.905 MB perf.data (2520 samples) ]

   #perf evlist -v
   cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type:
   IP|TID|TIME|CPU|PERIOD|REGS_INTR, read_format: ID, disabled: 1,
   inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, precise_ip: 3,
   sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol:
   1, bpf_event: 1, sample_regs_intr: 0xff0fff

Test on Icelake which support XMM registers collection.

   #perf record -I?
   available registers: AX BX CX DX SI DI BP SP IP FLAGS CS SS R8 R9 R10
   R11 R12 R13 R14 R15 XMM0 XMM1 XMM2 XMM3 XMM4 XMM5 XMM6 XMM7 XMM8 XMM9
   XMM10 XMM11 XMM12 XMM13 XMM14 XMM15

   Usage: perf record [<options>] [<command>]
    or: perf record [<options>] -- <command> [<options>]

    -I, --intr-regs[=<any register>]
                          sample selected machine registers on
   interrupt, use '-I?' to list register names

   #perf record -I
   [ perf record: Woken up 1 times to write data ]
   [ perf record: Captured and wrote 0.800 MB perf.data (318 samples) ]

   #perf evlist -v
   cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type:
   IP|TID|TIME|CPU|PERIOD|REGS_INTR, read_format: ID, disabled: 1,
   inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, precise_ip: 3,
   sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol:
   1, bpf_event: 1, sample_regs_intr: 0xffffffff00ff0fff

Committer notes:

Don't set attr.sample_period as a named struct init, as it is part of an
unnamed union in 'struct perf_event_attr', and doing so breaks the build
on older gcc versions, such as:

  gcc version 4.1.2 20080704 (Red Hat 4.1.2-55)
  gcc version 4.4.7 20120313 (Red Hat 4.4.7-23) (GCC)

  arch/x86/util/perf_regs.c: In function 'arch__intr_reg_mask':
  arch/x86/util/perf_regs.c:279: error: unknown field 'sample_period' specified in initializer
  cc1: warnings being treated as errors
  arch/x86/util/perf_regs.c:279: warning: missing braces around initializer
  arch/x86/util/perf_regs.c:279: warning: (near initialization for 'attr.<anonymous>')
Signed-off-by: default avatarKan Liang <kan.liang@linux.intel.com>
[ Only on a lenovo t480s, a skylake machine, where the XMM registers didn't show up in -I?/--user-regs=? as expected ]
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/1557865174-56264-3-git-send-email-kan.liang@linux.intel.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      6466ec14
    • Kan Liang's avatar
      perf parse-regs: Add generic support for arch__intr/user_reg_mask() · af785e75
      Kan Liang authored 
      There may be different register mask for use with intr or user on some
platforms, e.g. Icelake.

Add weak functions arch__intr_reg_mask() and arch__user_reg_mask() to
return intr and user register mask respectively.

Check mask before printing or comparing the register name.

Generic code always return PERF_REGS_MASK. No functional change.
Suggested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarKan Liang <kan.liang@linux.intel.com>
Tested-by: default avatarRavi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/1557865174-56264-2-git-send-email-kan.liang@linux.intel.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      af785e75
  3. 15 May, 2019 35 commits
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