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authorArnaldo Carvalho de Melo <acme@redhat.com>2009-01-26 16:00:40 -0200
committerIngo Molnar <mingo@elte.hu>2009-01-27 14:30:36 +0100
commit32c0bd9624115041cfec31c0436995418083090a (patch)
tree833dfe1e19338721d1043a2ecfa96a40703c0749 /block/Kconfig
parent157f9c00e88529ed84bd7d581a40d411e5414cf0 (diff)
downloadblackbird-op-linux-32c0bd9624115041cfec31c0436995418083090a.tar.gz
blackbird-op-linux-32c0bd9624115041cfec31c0436995418083090a.zip
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 <mingo@elte.hu> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'block/Kconfig')
-rw-r--r--block/Kconfig8
1 files changed, 8 insertions, 0 deletions
diff --git a/block/Kconfig b/block/Kconfig
index 0cbb3b88b59a..7cdaa1d72252 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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