[PATCH v4 0/2] perf tools: add 'perf irq' to measure the hardware interrupts

[Bixuan Cui]

When the hardware interrupt processing function is executed, the interrupt and 
preemption of current cpu are disabled. As a result, the task is suspended.
The execution of the hardware processing function takes a long time
(for example 5 ms), will affect the task scheduling performance.

This patches provides the 'perf irq' command to trace and calculate the time
consumed of the hardware irq function.

[verse]
'perf irq' [<options>] {record|report}

DESCRIPTION
-----------
There are several variants of 'perf irq':

  'perf irq record <command>' to record the irq handler events
  of an arbitrary workload.

  'perf irq report' to calculate the time consumed by each
   hardware interrupt processing function.

    Example usage:
        perf irq record -- sleep 1
        perf irq report

   By default it shows the individual irq events, including the irq name,
   cpu(execute the hardware interrupt processing function), time consumed,
   entry time and exit time for the each hardware irq:

   -------------------------------------------------------------------------------------------------------------------------------------------
     Irq name         |  CPU   | Time consume us | Handler entry time | Handler exit time
   -------------------------------------------------------------------------------------------------------------------------------------------
     enp2s0f2-tx-0    | [0006] |      0.000001 s |   6631263.313329 s |   6631263.313330 s
     megasas          | [0013] |      0.000003 s |   6631263.209564 s |   6631263.209567 s
     acpi             | [0016] |      0.000018 s |   6631263.085787 s |   6631263.085805 s

    And:
	perf irq --cpu 78 record -- sleep 1
	perf irq --cpu 78 report
   -------------------------------------------------------------------------------------------------------------------------------------------
     Irq name         |  CPU   | Time consume us | Handler entry time | Handler exit time
   -------------------------------------------------------------------------------------------------------------------------------------------
    enp134s0f0-TxRx-2 | [0078] |      0.000005 s |    693757.533189 s |    693757.533194 s


Changes from v4:
* Keep pairs of irq entry/exit per cpu;
* Add NUL-termination to the end of irq->irq_name when strncpy is used;
* Delete some unused declarations and parameters;

Changes from v3:
* Delete 'perf irq script' because its function can be implemented using
  'perf script';
* Add --cpu option for 'perf irq';

Changes from v2:
* Delete "-m", "1024" in __cmd_record();
* Change 'perf irq timeconsume <options>' to 'perf irq report <options>';
* Fix a error for tools/perf/Documentation/perf-irq.txt;

Bixuan Cui (2):
  perf tools: add 'perf irq' to measure the hardware interrupts
  perf tools: Add documentation for 'perf irq' command

 tools/perf/Build                      |   1 +
 tools/perf/Documentation/perf-irq.txt |  47 +++++
 tools/perf/builtin-irq.c              | 259 ++++++++++++++++++++++++++
 tools/perf/builtin.h                  |   1 +
 tools/perf/command-list.txt           |   1 +
 tools/perf/perf.c                     |   1 +
 6 files changed, 310 insertions(+)
 create mode 100644 tools/perf/Documentation/perf-irq.txt
 create mode 100644 tools/perf/builtin-irq.c

-- 
2.17.1