On Fri, May 31, 2013 at 10:47:23AM +0200, Robert Richter wrote: > From: Robert Richter <robert.rich...@calxeda.com> > > The default buffer size used to setup event buffers with perf tools is > 512k. Using the same buffer size for persistent events. This also > avoids failed mmap calls due to different buffer sizes. > > Signed-off-by: Robert Richter <robert.rich...@calxeda.com> > --- > kernel/events/persistent.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/kernel/events/persistent.c b/kernel/events/persistent.c > index 9075164..1e6c03a 100644 > --- a/kernel/events/persistent.c > +++ b/kernel/events/persistent.c > @@ -5,6 +5,9 @@ > > #include "internal.h" > > +/* 512 kiB: default perf tools memory size, see perf_evlist__mmap() */ > +#define CPU_BUFFER_NR_PAGES ((512 * 1024) / PAGE_SIZE) > + > static DEFINE_PER_CPU(struct list_head, pers_events); > > static struct perf_event * > @@ -151,7 +154,7 @@ int perf_add_persistent_event_by_id(int id) > attr->type = PERF_TYPE_TRACEPOINT; > attr->size = sizeof(*attr); > > - return perf_add_persistent_event(attr, 4); > + return perf_add_persistent_event(attr, CPU_BUFFER_NR_PAGES);
This one too - the 4 pages I chose then was purely arbitrary for I had no idea what size to pick. This clearly makes more sense. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
