Re: [PATCH] cpufreq: qoriq: optimize the CPU frequency switching time

On Thursday, June 04, 2015 12:06:36 PM Viresh Kumar wrote:

On 04-06-15, 14:25, Yuantian.Tang@freescale.com wrote:

quoted

From: Tang Yuantian <redacted>

Each time the CPU switches its frequency, the clock nodes in
DTS are walked through to find proper clock source. This is
very time-consuming, for example, it is up to 500+ us on T4240.
Besides, switching time varies from clock to clock.
To optimize this, each input clock of CPU is buffered, so that
it can be picked up instantly when needed.

Since for each CPU each input clock is stored in a pointer
which takes 4 or 8 bytes memory and normally there are several
input clocks per CPU, that will not take much memory as well.

Not sure how it got included in this form in the first place. :)

quoted

Signed-off-by: Tang Yuantian <redacted>
---
 drivers/cpufreq/qoriq-cpufreq.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

Queued up for 4.2, thanks!


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.