On Thu, 7 Jan 2021 10:32:48 +0200 "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote: > New man pages with documentation about: > tracefs_trace_is_on(); > tracefs_trace_on(); > tracefs_trace_off(); > tracefs_trace_on_fd(); > tracefs_trace_off_fd(); > > Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx> > --- > Documentation/libtracefs-traceon.txt | 143 +++++++++++++++++++++++++++ > 1 file changed, 143 insertions(+) > create mode 100644 Documentation/libtracefs-traceon.txt > > diff --git a/Documentation/libtracefs-traceon.txt b/Documentation/libtracefs-traceon.txt > new file mode 100644 > index 0000000..af4b7f7 > --- /dev/null > +++ b/Documentation/libtracefs-traceon.txt > @@ -0,0 +1,143 @@ > +libtracefs(3) > +============= > + > +NAME > +---- > +tracefs_trace_is_on, tracefs_trace_on, tracefs_trace_off, tracefs_trace_on_fd, > +tracefs_trace_off_fd - Functions to enable or disable tracing. > + > +SYNOPSIS > +-------- > +[verse] > +-- > +*#include <tracefs.h>* > + > +int *tracefs_trace_is_on*(struct tracefs_instance pass:[*]_instance_); > +int *tracefs_trace_on*(struct tracefs_instance pass:[*]_instance_); > +int *tracefs_trace_off*(struct tracefs_instance pass:[*]_instance_); > +int *tracefs_trace_on_fd*(int _fd_); > +int *tracefs_trace_off_fd*(int _fd_); > +-- > + > +DESCRIPTION > +----------- > +This set of functions can be used to check, enable or disable writing to the ring buffer in > +the given trace instance. The tracing is enabled when writing to the ring buffer is enabled. > + > +The _tracefs_trace_is_on()_ function checks if tracing is enabled for the given _instance_. If > +_instance_ is NULL, the top instance is used. > + > +The _tracefs_trace_on()_ and _tracefs_trace_off()_ functions set the tracing in the _instance_ > +to enable or disable state. If _instance_ is NULL, the top instance is used. > + > +The _tracefs_trace_on_fd()_ and _tracefs_trace_off_fd()_ functions set the tracing state to enable > +or disable using the given _fd_. This file descriptor must be opened for writing with > +*tracefs_instance_file_open*(3) for *tracing_on* file from desired trace instance. These functions > +are faster than *tracefs_trace_on* and *tracefs_trace_off*. Hmm, I think this should also add "tracefs_trace_on_get_fd()" that returns a file descriptor on "tracing_on" on the given instance opened with O_RDWR. fd = tracefs_trace_on_get_fd(NULL); tracefs_trace_on_fd(fd); close(fd); Would be the same as: tracefs_trace_on(NULL); -- Steve
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