On 02/04/2019 10:45, Qu Wenruo wrote: > OK, after some though, the overhead for a new tracepoint is pretty small. > The only overhead when the tracepoint is disabled is, a ktimer_get_ns() > call at the beginning of btrfs_tree_lock() and btrfs_tree_read_lock(). If you only need the ktime_get_ns() call for the tracepoint, you can wrap it in sth. like this IIRC: if (trace_btrfs_tree_lock_enabled()) start_time = ktime_get_ns(); [...] trace_btrfs_tree_lock(start_time, end_time); Byte, Johannes -- Johannes Thumshirn SUSE Labs Filesystems jthumshirn@xxxxxxx +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
