Hi Sebastian,
On Mon, May 13, 2013 at 07:53:42PM +0100, Sebastian Capella wrote:
> Pass residency information to the mcpm_cpu_suspend. The information
> is taken from the target_residency of the intended C-state.
>
> When a platform uses multiple powerdown cstates, the residency information
> indicates which powerdown state is targeted. Multiple powerdown cstate
> information can be maintained in the device tree and the vendor specific
> handling will then have enough information to determine what power state to
> enter without needing additional changes to the big_little framework.
>
> Signed-off-by: Sebastian Capella <sebastian.cape...@linaro.org>
> ---
> drivers/cpuidle/arm_big_little.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpuidle/arm_big_little.c
> b/drivers/cpuidle/arm_big_little.c
> index a430800..8332b05 100644
> --- a/drivers/cpuidle/arm_big_little.c
> +++ b/drivers/cpuidle/arm_big_little.c
I could not find a branch that contains this file. Which git tree and branch
are you using?
> @@ -89,7 +89,7 @@ static int notrace bl_powerdown_finisher(unsigned long arg)
> unsigned int cpu = mpidr & 0xf;
>
> mcpm_set_entry_vector(cpu, cluster, cpu_resume);
> - mcpm_cpu_suspend(0); /* 0 should be replaced with better value here */
> + mcpm_cpu_suspend(arg);
> return 1;
> }
>
> @@ -107,6 +107,7 @@ static int bl_enter_powerdown(struct cpuidle_device *dev,
> {
> struct timespec ts_preidle, ts_postidle, ts_idle;
> int ret;
> + struct cpuidle_state *state = &drv->states[idx];
>
> /* Used to keep track of the total time in idle */
> getnstimeofday(&ts_preidle);
> @@ -117,7 +118,8 @@ static int bl_enter_powerdown(struct cpuidle_device *dev,
>
> clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu);
>
> - ret = cpu_suspend((unsigned long) dev, bl_powerdown_finisher);
> + ret = cpu_suspend((unsigned long) state->target_residency,
> + bl_powerdown_finisher);
I don't think you should pass the target residency here but the intended
C-state. Think about what will happen when you run this in a guest kernel: is
the target_residency the same if the guest has been migrated from a big core
that might have a faster execution of the down/up path to a little core that
is slower? The intended C-state should stay the same, regardless of the actual
time it takes to get there and out, which affects the actual time spent inside
the state.
Best regards,
Liviu
--
====================
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| fix the world, |
| but they're not |
| giving me the |
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