perf kwork: New tool to trace time properties of kernel work (such as softirq, and workqueue)

The 'perf kwork' tool is used to trace time properties of kernel work
(such as irq, softirq, and workqueue), including runtime, latency, and
timehist, using the infrastructure in the perf tools to allow tracing
extra targets.

This is the first commit to reuse the 'perf record' framework code to
implement a simple record function, kwork is not supported currently.

Test cases:

  # perf

   usage: perf [--version] [--help] [OPTIONS] COMMAND [ARGS]

   The most commonly used perf commands are:
  <SNIP>
     iostat          Show I/O performance metrics
     kallsyms        Searches running kernel for symbols
     kmem            Tool to trace/measure kernel memory properties
     kvm             Tool to trace/measure kvm guest os
     kwork           Tool to trace/measure kernel work properties (latencies)
     list            List all symbolic event types
     lock            Analyze lock events
     mem             Profile memory accesses
     record          Run a command and record its profile into perf.data
  <SNIP>
   See 'perf help COMMAND' for more information on a specific command.

  # perf kwork

   Usage: perf kwork [<options>] {record}

      -D, --dump-raw-trace  dump raw trace in ASCII
      -f, --force           don't complain, do it
      -k, --kwork <kwork>   list of kwork to profile
      -v, --verbose         be more verbose (show symbol address, etc)

  # perf kwork record -- sleep 1
  [ perf record: Woken up 0 times to write data ]
  [ perf record: Captured and wrote 1.787 MB perf.data ]

Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220709015033.38326-2-yangjihong1@huawei.com
[ Add {} for multiline if blocks ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/tools/perf/Documentation/perf-kwork.txt b/tools/perf/Documentation/perf-kwork.txt
new file mode 100644
index 000000000000..dc1e36da57bb
--- /dev/null
+++ b/tools/perf/Documentation/perf-kwork.txt
@@ -0,0 +1,43 @@
+perf-kowrk(1)
+=============
+
+NAME
+----
+perf-kwork - Tool to trace/measure kernel work properties (latencies)
+
+SYNOPSIS
+--------
+[verse]
+'perf kwork' {record}
+
+DESCRIPTION
+-----------
+There are several variants of 'perf kwork':
+
+  'perf kwork record <command>' to record the kernel work
+  of an arbitrary workload.
+
+    Example usage:
+        perf kwork record -- sleep 1
+
+OPTIONS
+-------
+-D::
+--dump-raw-trace=::
+	Display verbose dump of the sched data.
+
+-f::
+--force::
+	Don't complain, do it.
+
+-k::
+--kwork::
+	List of kwork to profile
+
+-v::
+--verbose::
+	Be more verbose. (show symbol address, etc)
+
+SEE ALSO
+--------
+linkperf:perf-record[1]