[lkml]   [2018]   [Jul]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] PM / devfreq: Generic cpufreq governor
On Sat, Jul 28, 2018 at 5:56 AM, Saravana Kannan <> wrote:
> Many CPU architectures have caches that can scale independent of the CPUs.
> Frequency scaling of the caches is necessary to make sure the cache is not
> a performance bottleneck that leads to poor performance and power. The same
> idea applies for RAM/DDR.
> To achieve this, this patch adds a generic devfreq governor that can listen
> to the frequency transitions of each CPU frequency domain and then adjusts
> the frequency of the cache (or any devfreq device) based on the frequency
> of the CPUs.
> To decide the frequency of the device, the governor does one of the
> following:
> * Uses a CPU frequency to device frequency mapping table
> - Either one mapping table used for all CPU freq policies (typically used
> for system with homogeneous cores/clusters that have the same OPPs.
> - One mapping table per CPU freq policy (typically used for ASMP systems
> with heterogeneous CPUs with different OPPs)
> OR
> * Scales the device frequency in proportion to the CPU frequency. So, if
> the CPUs are running at their max frequency, the device runs at its max
> frequency. If the CPUs are running at their min frequency, the device
> runs at its min frequency. And interpolated for frequencies in between.

While not having looked at the details of the patch yet, I would
change the name of the feature to "Generic cpufreq transition
governor" to make it somewhat less ambiguous.

 \ /
  Last update: 2018-07-29 12:52    [W:0.156 / U:2.316 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site