Messages in this thread | | | Date | Fri, 20 Feb 2009 11:40:04 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] tracing/function-graph-tracer: make set_graph_function file support ftrace regex |
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> Impact: trace only functions matching a pattern > > The set_graph_function file let one to trace only one or several > chosen functions and follow all their code flow. > > Currently, only a constant function name is allowed so this patch > allows the ftrace_regex functions: > > _ matches all functions that end with "name": > echo *name > set_graph_function > > _ matches all functions that begin with "name": > echo name* > set_graph_function > > _ matches all functions that contains "name": > echo *name* > set_graph_function > > Example: > > echo mutex* > set_graph_function > > 0) | mutex_lock_nested() { > 0) 0.563 us | __might_sleep(); > 0) 2.072 us | } > 0) | mutex_unlock() { > 0) 1.036 us | __mutex_unlock_slowpath(); > 0) 2.433 us | } > 0) | mutex_unlock() { > 0) 0.691 us | __mutex_unlock_slowpath(); > 0) 1.787 us | } > 0) | mutex_lock_interruptible_nested() { > 0) 0.548 us | __might_sleep(); > 0) 1.945 us | } > > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > --- > kernel/trace/ftrace.c | 56 +++++++++++++++++++++++++++++++++--------------- > 1 files changed, 38 insertions(+), 18 deletions(-)
Applied, thanks Frederic!
I'm wondering about the following: the whole set_graph_function method is limited (to FTRACE_GRAPH_MAX_FUNCS, 32 entries), is not scalable (we walk the array of functions at every function trace point), has a separate API, etc.
Wouldnt we off better with a good, generic function attributes hash, and an extension to the generic regexp parser to enable the setting of those attributes? One such attribute could be the 'expand child function'
Ingo
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