Re: [PATCH v5 05/11] arm-cci PMU: Delay counter writes to pmu_enable

From	"Suzuki K. Poulose" <Suzuki.Poulose@arm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v5 05/11] arm-cci PMU: Delay counter writes to pmu_enable
Date	2016-01-11 12:10 +0100
Message-ID	<qPIwj-1vs-39@gated-at.bofh.it> (permalink)
References	<qNbXP-2ZX-3@gated-at.bofh.it> <qNbXR-2ZX-41@gated-at.bofh.it> <qNiZk-7GT-11@gated-at.bofh.it> <qNwzg-j5-11@gated-at.bofh.it> <qPIcX-17S-25@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On 11/01/16 10:46, Mark Rutland wrote:
> On Tue, Jan 05, 2016 at 09:59:13AM +0000, Suzuki K. Poulose wrote:
>> On 04/01/16 19:24, Mark Rutland wrote:
>>> On Mon, Jan 04, 2016 at 11:54:44AM +0000, Suzuki K. Poulose wrote:
>> The pmu is not disabled while we are in overflow irq handler. Hence there may
>> not be a pmu_enable() which would set the period for the counter which
>> overflowed, if defer the write in that case. Is that assumption wrong ?
>
> As the driver stands today, yes.
>
> However, wouldn't it make more sense to disable the PMU for the overflow
> handler, such that we can reuse the batching logic?

None of the PMU drivers do that AFAIK. Hence, didn't want to change it for
CCI. We could use the batching logic, if decide to do so. I can go ahead
with that if there are no other side effects with that.

Suzuki

Thread

[PATCH v5 05/11] arm-cci PMU: Delay counter writes to pmu_enable "Suzuki K. Poulose" <suzuki.poulose@arm.com> - 2016-01-04 13:00 +0100
  Re: [PATCH v5 05/11] arm-cci PMU: Delay counter writes to pmu_enable Mark Rutland <mark.rutland@arm.com> - 2016-01-04 20:30 +0100
    Re: [PATCH v5 05/11] arm-cci PMU: Delay counter writes to pmu_enable "Suzuki K. Poulose" <Suzuki.Poulose@arm.com> - 2016-01-05 11:00 +0100
      Re: [PATCH v5 05/11] arm-cci PMU: Delay counter writes to pmu_enable Mark Rutland <mark.rutland@arm.com> - 2016-01-11 11:50 +0100
        Re: [PATCH v5 05/11] arm-cci PMU: Delay counter writes to pmu_enable "Suzuki K. Poulose" <Suzuki.Poulose@arm.com> - 2016-01-11 12:10 +0100
          Re: [PATCH v5 05/11] arm-cci PMU: Delay counter writes to pmu_enable Mark Rutland <mark.rutland@arm.com> - 2016-01-11 12:30 +0100
            Re: [PATCH v5 05/11] arm-cci PMU: Delay counter writes to pmu_enable "Suzuki K. Poulose" <Suzuki.Poulose@arm.com> - 2016-01-11 19:20 +0100

csiph-web