Add option to allow user to control analysis window. e.g., collect data
for time window and analyze a segment of interest within that window.

Committer notes:

Testing it:

Using the perf.data file captured via 'perf kmem record':

  # perf report --header-only
  # ========
  # captured on: Tue Nov 29 16:01:53 2016
  # hostname : jouet
  # os release : 4.8.8-300.fc25.x86_64
  # perf version : 4.9.rc6.g5a6aca
  # arch : x86_64
  # nrcpus online : 4
  # nrcpus avail : 4
  # cpudesc : Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz
  # cpuid : GenuineIntel,6,61,4
  # total memory : 20254660 kB
  # cmdline : /home/acme/bin/perf kmem record usleep 1
  # event : name = kmem:kmalloc, , id = { 931980, 931981, 931982, 931983 }, type = 2, size = 112, config = 0x1b9, { sample_period, sample_freq } = 1, sample_typ
  # event : name = kmem:kmalloc_node, , id = { 931984, 931985, 931986, 931987 }, type = 2, size = 112, config = 0x1b7, { sample_period, sample_freq } = 1, sampl
  # event : name = kmem:kfree, , id = { 931988, 931989, 931990, 931991 }, type = 2, size = 112, config = 0x1b5, { sample_period, sample_freq } = 1, sample_type
  # event : name = kmem:kmem_cache_alloc, , id = { 931992, 931993, 931994, 931995 }, type = 2, size = 112, config = 0x1b8, { sample_period, sample_freq } = 1, s
  # event : name = kmem:kmem_cache_alloc_node, , id = { 931996, 931997, 931998, 931999 }, type = 2, size = 112, config = 0x1b6, { sample_period, sample_freq } =
  # event : name = kmem:kmem_cache_free, , id = { 932000, 932001, 932002, 932003 }, type = 2, size = 112, config = 0x1b4, { sample_period, sample_freq } = 1, sa
  # HEADER_CPU_TOPOLOGY info available, use -I to display
  # HEADER_NUMA_TOPOLOGY info available, use -I to display
  # pmu mappings: cpu = 4, intel_pt = 7, intel_bts = 6, uncore_arb = 13, cstate_pkg = 15, breakpoint = 5, uncore_cbox_1 = 12, power = 9, software = 1, uncore_im
  # HEADER_CACHE info available, use -I to display
  # missing features: HEADER_BRANCH_STACK HEADER_GROUP_DESC HEADER_AUXTRACE HEADER_STAT
  # ========
  #
  # # Looking at just the histogram entries for the first event:
  #
  # perf report  | head -33
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 40  of event 'kmem:kmalloc'
  # Event count (approx.): 40
  #
  # Overhead  Trace output
  # ........  ...............................................................................................................
  #
    37.50%  call_site=ffffffffb91ad3c7 ptr=0xffff88895fc05000 bytes_req=4096 bytes_alloc=4096 gfp_flags=GFP_KERNEL
    10.00%  call_site=ffffffffb9258416 ptr=0xffff888a1dc61f00 bytes_req=240 bytes_alloc=256 gfp_flags=GFP_KERNEL|__GFP_ZERO
     7.50%  call_site=ffffffffb9258416 ptr=0xffff888a2640ac00 bytes_req=240 bytes_alloc=256 gfp_flags=GFP_KERNEL|__GFP_ZERO
     2.50%  call_site=ffffffffb92759ba ptr=0xffff888a26776000 bytes_req=4096 bytes_alloc=4096 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb9276864 ptr=0xffff8886f6b82600 bytes_req=136 bytes_alloc=192 gfp_flags=GFP_KERNEL|__GFP_ZERO
     2.50%  call_site=ffffffffb9276903 ptr=0xffff888aefcf0460 bytes_req=32 bytes_alloc=32 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb92ad0ce ptr=0xffff888756c98a00 bytes_req=392 bytes_alloc=512 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb92ad0ce ptr=0xffff888756c9ba00 bytes_req=504 bytes_alloc=512 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb92ad301 ptr=0xffff888a31747600 bytes_req=128 bytes_alloc=128 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb92ad511 ptr=0xffff888a9d26a2a0 bytes_req=28 bytes_alloc=32 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb936a7fb ptr=0xffff88873e8c11a0 bytes_req=24 bytes_alloc=32 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb936a7fb ptr=0xffff88873e8c12c0 bytes_req=24 bytes_alloc=32 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb936a7fb ptr=0xffff88873e8c1540 bytes_req=24 bytes_alloc=32 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb936a7fb ptr=0xffff88873e8c15a0 bytes_req=24 bytes_alloc=32 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb936a7fb ptr=0xffff88873e8c15e0 bytes_req=24 bytes_alloc=32 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb936a7fb ptr=0xffff88873e8c16e0 bytes_req=24 bytes_alloc=32 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb936a7fb ptr=0xffff88873e8c1c20 bytes_req=24 bytes_alloc=32 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb936a7fb ptr=0xffff888a9d26a2a0 bytes_req=24 bytes_alloc=32 gfp_flags=GFP_KERNEL
     2.50%  call_site=ffffffffb9373e66 ptr=0xffff8889f1931240 bytes_req=64 bytes_alloc=64 gfp_flags=GFP_ATOMIC|__GFP_ZERO
     2.50%  call_site=ffffffffb9373e66 ptr=0xffff8889f1931980 bytes_req=64 bytes_alloc=64 gfp_flags=GFP_ATOMIC|__GFP_ZERO
     2.50%  call_site=ffffffffb9373e66 ptr=0xffff8889f1931a00 bytes_req=64 bytes_alloc=64 gfp_flags=GFP_ATOMIC|__GFP_ZERO

  #
  # # And then limiting using the example for 'perf kmem stat --time' used
  # # in the previous changeset committer note we see that there were no
  # # kmem:kmalloc in that last part of the file, but there were some
  # # kmem:kmem_cache_alloc ones:
  #
  # perf report --time 20119.782088, --stdio
  #
  # Total Lost Samples: 0
  #
  # Samples: 0  of event 'kmem:kmalloc'
  # Event count (approx.): 0
  #
  # Overhead  Trace output
  # ........  ............
  #

  # Samples: 0  of event 'kmem:kmalloc_node'
  # Event count (approx.): 0
  #
  # Overhead  Trace output
  # ........  ............
  #

  # Samples: 0  of event 'kmem:kfree'
  # Event count (approx.): 0
  #
  # Overhead  Trace output
  # ........  ............
  #

  # Samples: 8  of event 'kmem:kmem_cache_alloc'
  # Event count (approx.): 8
  #
  # Overhead  Trace output
  # ........  ..................................................................................................................
  #
    75.00%  call_site=ffffffffb9333b42 ptr=0xffff888bdf1a39c0 bytes_req=48 bytes_alloc=48 gfp_flags=GFP_NOFS|__GFP_ZERO
    12.50%  call_site=ffffffffb90ad33a ptr=0xffff8889f071f6e0 bytes_req=160 bytes_alloc=160 gfp_flags=GFP_ATOMIC|__GFP_NOTRACK
    12.50%  call_site=ffffffffb9287cc1 ptr=0xffff8889b12722d8 bytes_req=104 bytes_alloc=104 gfp_flags=GFP_NOFS|__GFP_ZERO
  #
Signed-off-by: David Ahern <dsahern@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1480439746-42695-7-git-send-email-dsahern@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>