On Tue, May 30, 2017 at 11:45:12AM +0200, Peter Zijlstra wrote: > > Or is the simple patch below good enough? > > The below seems to be the correct thing. It is rather unfortunate that > this would break/significantly change existing semantics :/
The "existing semantics" as in ignoring the PERF_SAMPLE_READ in sample_type, even though it wasn't implemented? It seems reasonable to me. If you really worry about it could drop a printk_once in and see if it triggers anywhere (and if yes drop the if completely) The patch looks good to me. Please consider adding it. I have some patches to use this in perf stat, will submit later. -Andi