Re: [PATCH] sparc: perf: fix updated event period in response to PERF_EVENT_IOC_PERIOD
From: David Miller
Date: Mon Jun 03 2019 - 01:20:42 EST
From: Young Xiao <92siuyang@xxxxxxxxx>
Date: Wed, 29 May 2019 10:21:48 +0800
> The PERF_EVENT_IOC_PERIOD ioctl command can be used to change the
> sample period of a running perf_event. Consequently, when calculating
> the next event period, the new period will only be considered after the
> previous one has overflowed.
> This patch changes the calculation of the remaining event ticks so that
> they are offset if the period has changed.
> See commit 3581fe0ef37c ("ARM: 7556/1: perf: fix updated event period in
> response to PERF_EVENT_IOC_PERIOD") for details.
> Signed-off-by: Young Xiao <92siuyang@xxxxxxxxx>