Re: [RFC PATCH 1/1] kernel/events: Introduce IOC_COUNT_RECORDS

[Peter Zijlstra]

On Tue, Jun 06, 2017 at 08:46:28PM +0530, Naveen N. Rao wrote:
> Many perf sideband events (context switches, namespaces, ...) are useful
> by themselves without the need for subscribing to any overflow events.
> However, it is not possible to subscribe for notifications when such
> records are logged into the ring buffer. Introduce IOC_COUNT_RECORDS as
> a way to request this.
> 
> With IOC_COUNT_RECORDS set, IOC_REFRESH takes the number of records
> after which to generate a notification, rather than the number of
> overflow events.

You forgot to explain why? As is I'm not terribly excited to have more
'crud' in that output path.