From: Sumit Gupta <sumitg@nvidia.com>
To: Jon Hunter <jonathanh@nvidia.com>, <rafael@kernel.org>,
<viresh.kumar@linaro.org>, <linux-pm@vger.kernel.org>,
<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: <treding@nvidia.com>, <bbasu@nvidia.com>, <amiettinen@nvidia.com>,
"Sumit Gupta" <sumitg@nvidia.com>
Subject: Re: [Patch v2 2/2] cpufreq: tegra194: use refclk delta based loop instead of udelay
Date: Sat, 2 Sep 2023 01:23:12 +0530 [thread overview]
Message-ID: <8522b877-3f6f-8225-4a9f-512d15b3d477@nvidia.com> (raw)
In-Reply-To: <8c26f493-76d4-086e-c353-2f60a4ef7a72@nvidia.com>
On 01/09/23 23:29, Jon Hunter wrote:
>
> On 01/09/2023 17:41, Sumit Gupta wrote:
>> Use reference clock count based loop instead of "udelay()" for
>> sampling of counters to improve the accuracy of re-generated CPU
>> frequency. "udelay()" internally calls "WFE" which stops the
>> counters and results in bigger delta between the last set freq
>> and the re-generated value from counters. The counter sampling
>> window used in loop is the minimum number of reference clock
>> cycles which is known to give a stable value of CPU frequency.
>> The change also helps to reduce the sampling window from "500us"
>> to "<50us".
>>
>> Suggested-by: Antti Miettinen <amiettinen@nvidia.com>
>> Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
>> ---
>
> Same here.
>
> Jon
>
This patch is newly added in v2.
Thank you,
Sumit Gupta
next prev parent reply other threads:[~2023-09-01 19:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-01 16:41 [Patch v2 0/2] Improvements to the Tegra CPUFREQ driver Sumit Gupta
2023-09-01 16:41 ` [Patch v2 1/2] cpufreq: tegra194: save CPU data to avoid repeated SMP calls Sumit Gupta
2023-09-01 17:58 ` Jon Hunter
2023-09-01 19:51 ` Sumit Gupta
2023-09-28 7:05 ` Viresh Kumar
2023-09-29 14:17 ` Sumit Gupta
2023-10-03 5:00 ` Viresh Kumar
2023-10-04 14:11 ` Sumit Gupta
2023-09-01 16:41 ` [Patch v2 2/2] cpufreq: tegra194: use refclk delta based loop instead of udelay Sumit Gupta
2023-09-01 17:59 ` Jon Hunter
2023-09-01 19:53 ` Sumit Gupta [this message]
2023-09-19 11:28 ` [Patch v2 0/2] Improvements to the Tegra CPUFREQ driver Sumit Gupta
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