From mboxrd@z Thu Jan 1 00:00:00 1970 From: ashwinc@codeaurora.org (Ashwin Chaugule) Date: Thu, 23 Feb 2012 11:12:59 -0500 Subject: [PATCH] ARM: perf: add PMU hotplug notifier In-Reply-To: <20120223160450.GL29450@mudshark.cambridge.arm.com> References: <4F4661E2.9020405@codeaurora.org> <4F4662AD.6030306@codeaurora.org> <20120223160450.GL29450@mudshark.cambridge.arm.com> Message-ID: <4F46658B.3030903@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2/23/2012 11:04 AM, Will Deacon wrote: > > Ok. Note that the perf core will actually destroy perf events on a hotplug > down notification, so profiling runs will be dead on that core even if it > comes back up. > > This patch just ensures that we have a sane state in the control registers > given that their state is UNKNOWN out of reset. Adding full hotplug support > to perf (that is, supporting hotplug events during a run and representing > that in a meaningful way) is a larger issue. > >>> I'll send a link to my code once the git server is up. It's a bit flaky today. > > Ok, cool. Are you happy with me to proceed with the current code for the > time being? > Sure. We'll need to be able to distinguish between a hotplug and a CPU power-collapse / deep sleep / what-have-you state in this code at some point since they all have a different effect on the PMU regs. Cheers, Ashwin -- Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.