* blktrace: the ftrace interface needs CONFIG_TRACING
@ 2009-01-26 18:00 Arnaldo Carvalho de Melo
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From: Arnaldo Carvalho de Melo @ 2009-01-26 18:00 UTC (permalink / raw)
To: Jens Axboe; +Cc: Ingo Molnar, Linux Kernel Mailing List
Impact: Fix Kconfig selection for blktrace
Also mention in the help text that blktrace now can be used using
the ftrace interface.
Cc: Jens Axboe <jens.axboe@oracle.com>
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/block/Kconfig b/block/Kconfig
index 0cbb3b8..7cdaa1d 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -50,6 +50,8 @@ config BLK_DEV_IO_TRACE
select RELAY
select DEBUG_FS
select TRACEPOINTS
+ select TRACING
+ select STACKTRACE
help
Say Y here if you want to be able to trace the block layer actions
on a given queue. Tracing allows you to see any traffic happening
@@ -58,6 +60,12 @@ config BLK_DEV_IO_TRACE
git://git.kernel.dk/blktrace.git
+ Tracing also is possible using the ftrace interface, e.g.:
+
+ echo 1 > /sys/block/sda/sda1/trace/enable
+ echo blk > /sys/kernel/debug/tracing/current_tracer
+ cat /sys/kernel/debug/tracing/trace_pipe
+
If unsure, say N.
config BLK_DEV_BSG
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2009-01-26 18:00 blktrace: the ftrace interface needs CONFIG_TRACING Arnaldo Carvalho de Melo
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