tracing/fastboot: improve help text

Improve the help text of the boot tracer.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 11fd03a..1cb3e1f 100644 (file)
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -127,12 +127,17 @@ config BOOT_TRACER
        select TRACING
        help
          This tracer helps developers to optimize boot times: it records
-         the timings of the initcalls. Its aim is to be parsed by the
-         /scripts/bootgraph.pl tool to produce pretty graphics about
-         boot inefficiencies, giving a visual representation of the
-         delays during initcalls. Note that tracers self tests can't
-         be enabled if this tracer is selected since only one tracer
-         should touch the tracing buffer at a time.
+         the timings of the initcalls and traces key events and the identity
+         of tasks that can cause boot delays, such as context-switches.
+
+         Its aim is to be parsed by the /scripts/bootgraph.pl tool to
+         produce pretty graphics about boot inefficiencies, giving a visual
+         representation of the delays during initcalls - but the raw
+         /debug/tracing/trace text output is readable too.
+
+         ( Note that tracing self tests can't be enabled if this tracer is
+           selected, because the self-tests are an initcall as well and that
+           would invalidate the boot trace. )
 
 config STACK_TRACER
        bool "Trace max stack"