linux-imx

perf script: Allow specifying the files to process guest samples

The 'perf kvm' command set up things so that we can record, report, top,
etc, but not 'script', so make 'perf script' be able to process samples
by allowing to pass guest kallsyms, vmlinux, modules, etc, and if at
least one of those is provided, set perf_guest to true so that guest
samples get properly resolved.

Testing it:

  # perf kvm --guest --guestkallsyms /wb/rhel6.kallsyms --guestmodules /wb/rhel6.modules record -e cycles:Gk
^C[ perf record: Woken up 7 times to write data ]
  [ perf record: Captured and wrote 3.602 MB perf.data.guest (10492 samples) ]

  #
  # perf evlist -i perf.data.guest
cycles:Gk
  # perf evlist -v -i perf.data.guest
cycles:Gk: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD, read_format: ID, disabled: 1, inherit: 1, exclude_user: 1, exclude_hv: 1, mmap: 1, comm: 1, freq: 1, task: 1, sample_id_all: 1, exclude_host: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1
  #
  # perf kvm --guestkallsyms /wb/rhel6.kallsyms --guestmodules /wb/rhel6.modules report --stdio -s sym | head -30
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 10K of event 'cycles:Gk'
  # Event count (approx.): 2434201408
  #
  # Overhead  Symbol
  # ........  ..............................................
  #
      11.93%  [g] avtab_search_node
       3.95%  [g] sidtab_context_to_sid
       2.41%  [g] n_tty_write
       2.20%  [g] _spin_unlock_irqrestore
       1.37%  [g] _aesni_dec4
       1.33%  [g] kmem_cache_alloc
       1.07%  [g] native_write_cr0
       0.99%  [g] kfree
       0.95%  [g] _spin_lock
       0.91%  [g] __memset
       0.87%  [g] schedule
       0.83%  [g] _spin_lock_irqsave
       0.76%  [g] __kmalloc
       0.67%  [g] avc_has_perm_noaudit
       0.66%  [g] kmem_cache_free
       0.65%  [g] glue_xts_crypt_128bit
       0.59%  [g] __d_lookup
       0.59%  [g] __audit_syscall_exit
       0.56%  [g] __memcpy
  #

Then, when trying to use perf script to generate a python script and
then process the events after adding a python hook for non-tracepoint
events:

  # perf script -i perf.data.guest -g python
  generated Python script: perf-script.py
  # vim perf-script.py
  # tail -2 perf-script.py
  def process_event(param_dict):
        print(param_dict["symbol"])
  #
  # perf script -i perf.data.guest -s perf-script.py  | head
  in trace_begin
  vmx_vmexit
  vmx_vmexit
  vmx_vmexit
  vmx_vmexit
  vmx_vmexit
  vmx_vmexit
  vmx_vmexit
  vmx_vmexit
  vmx_vmexit
  231
  #

We'd see just the vmx_vmexit, i.e. the samples from the guest don't show
up.

After this patch:

  # perf script --guestkallsyms /wb/rhel6.kallsyms --guestmodules /wb/rhel6.modules -i perf.data.guest -s perf-script.py 2> /dev/null | head -30
  in trace_begin
  apic_timer_interrupt
  apic_timer_interrupt
  apic_timer_interrupt
  apic_timer_interrupt
  apic_timer_interrupt
  save_args
  do_timer
  drain_array
  inode_permission
  avc_has_perm_noaudit
  run_timer_softirq
  apic_timer_interrupt
  apic_timer_interrupt
  apic_timer_interrupt
  apic_timer_interrupt
  apic_timer_interrupt
  kvm_guest_apic_eoi_write
  run_posix_cpu_timers
  _spin_lock
  handle_pte_fault
  rcu_irq_enter
  delay_tsc
  delay_tsc
  native_read_tsc
  apic_timer_interrupt
  sys_open
  internal_add_timer
  list_del
  rcu_exit_nohz
  #

Jiri Olsa noticed we need to set 'perf_guest' to true if we want to
process guest samples and I made it be set if one of the guest files
settings get set via the command line options added in this patch, that
match those present in the 'perf kvm' command.

We probably want to have 'perf record', 'perf report' etc to notice that
there are guest samples and do the right thing, which is to look for
files with some suffix that make it be associated with the guest used to
collect the samples, i.e. if a vmlinux file is passed, we can get the
build-id from it, if not some other identifier or simply looking for
"kallsyms.guest", for instance, in the current directory.

Reported-by: Mariano Pache <npache@redhat.com>
Tested-by: Mariano Pache <npache@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Cc: Ali Raza <alirazabhutta.10@gmail.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Joe Mario <jmario@redhat.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Orran Krieger <okrieger@redhat.com>
Cc: Ramkumar Ramachandra <artagnon@gmail.com>
Cc: Yunlong Song <yunlong.song@huawei.com>
Link: https://lkml.kernel.org/n/tip-d54gj64rerlxcqsrod05biwn@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>