From 32c0bd9624115041cfec31c0436995418083090a Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Mon, 26 Jan 2009 16:00:40 -0200 Subject: blktrace: the ftrace interface needs CONFIG_TRACING Impact: build fix Also mention in the help text that blktrace now can be used using the ftrace interface. Reported-by: Ingo Molnar Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Ingo Molnar --- block/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'block/Kconfig') diff --git a/block/Kconfig b/block/Kconfig index 0cbb3b88b59..7cdaa1d7225 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 -- cgit v1.2.3