Phylib uses workqueues for multiple purposes. There is no real dependency of scheduling these on the cpu which scheduled them.
On a idle system, it is observed that and idle cpu wakes up many times just to service this work. It would be better if we can schedule it on a cpu which isn't idle to save on power.
By idle cpu (from scheduler's perspective) we mean: - Current task is idle task - nr_running == 0 - wake_list is empty
This patch replaces the schedule_work() and schedule_delayed_work() routines with their queue_[delayed_]work_on_any_cpu() siblings with system_wq as parameter.
These routines would look for the closest (via scheduling domains) non-idle cpu (non-idle from schedulers perspective). If the current cpu is not idle or all cpus are idle, work will be scheduled on local cpu.
Cc: "David S. Miller" davem@davemloft.net Cc: netdev@vger.kernel.org Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- drivers/net/phy/phy.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c index 298b4c2..a517706 100644 --- a/drivers/net/phy/phy.c +++ b/drivers/net/phy/phy.c @@ -439,7 +439,7 @@ void phy_start_machine(struct phy_device *phydev, { phydev->adjust_state = handler;
- schedule_delayed_work(&phydev->state_queue, HZ); + queue_delayed_work_on_any_cpu(system_wq, &phydev->state_queue, HZ); }
/** @@ -527,7 +527,7 @@ static irqreturn_t phy_interrupt(int irq, void *phy_dat) disable_irq_nosync(irq); atomic_inc(&phydev->irq_disable);
- schedule_work(&phydev->phy_queue); + queue_work_on_any_cpu(system_wq, &phydev->phy_queue);
return IRQ_HANDLED; } @@ -682,7 +682,7 @@ static void phy_change(struct work_struct *work)
/* reschedule state queue work to run as soon as possible */ cancel_delayed_work_sync(&phydev->state_queue); - schedule_delayed_work(&phydev->state_queue, 0); + queue_delayed_work_on_any_cpu(system_wq, &phydev->state_queue, 0);
return;
@@ -966,7 +966,8 @@ void phy_state_machine(struct work_struct *work) if (err < 0) phy_error(phydev);
- schedule_delayed_work(&phydev->state_queue, PHY_STATE_TIME * HZ); + queue_delayed_work_on_any_cpu(system_wq, &phydev->state_queue, + PHY_STATE_TIME * HZ); }
static inline void mmd_phy_indirect(struct mii_bus *bus, int prtad, int devad,