2020-11-28 18:04:33

by Shenming Lu

[permalink] [raw]
Subject: [PATCH v2 1/2] irqchip/gic-v4.1: Reduce the delay time of the poll on the GICR_VPENDBASER.Dirty bit

The 10 delay_us of the poll on the GICR_VPENDBASER.Dirty bit is too
high, which might greatly affect the total scheduling latency of a
vCPU in our measurement. So we reduce it to 1 to lessen the impact.

Signed-off-by: Shenming Lu <[email protected]>
---
drivers/irqchip/irq-gic-v3-its.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 0fec31931e11..22f427135c6b 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -3809,7 +3809,7 @@ static void its_wait_vpt_parse_complete(void)
WARN_ON_ONCE(readq_relaxed_poll_timeout_atomic(vlpi_base + GICR_VPENDBASER,
val,
!(val & GICR_VPENDBASER_Dirty),
- 10, 500));
+ 1, 500));
}

static void its_vpe_schedule(struct its_vpe *vpe)
--
2.23.0


Subject: [irqchip: irq/irqchip-next] irqchip/gic-v4.1: Reduce the delay when polling GICR_VPENDBASER.Dirty

The following commit has been merged into the irq/irqchip-next branch of irqchip:

Commit-ID: 0b39498230ae53e6af981141be99f4c7d5144de6
Gitweb: https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/0b39498230ae53e6af981141be99f4c7d5144de6
Author: Shenming Lu <[email protected]>
AuthorDate: Sat, 28 Nov 2020 22:18:56 +08:00
Committer: Marc Zyngier <[email protected]>
CommitterDate: Fri, 11 Dec 2020 14:47:10

irqchip/gic-v4.1: Reduce the delay when polling GICR_VPENDBASER.Dirty

The 10us delay of the poll on the GICR_VPENDBASER.Dirty bit is too
high, which might greatly affect the total scheduling latency of a
vCPU in our measurement. So we reduce it to 1 to lessen the impact.

Signed-off-by: Shenming Lu <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
drivers/irqchip/irq-gic-v3-its.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 4069c21..d74ef41 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -3808,7 +3808,7 @@ static void its_wait_vpt_parse_complete(void)
WARN_ON_ONCE(readq_relaxed_poll_timeout_atomic(vlpi_base + GICR_VPENDBASER,
val,
!(val & GICR_VPENDBASER_Dirty),
- 10, 500));
+ 1, 500));
}

static void its_vpe_schedule(struct its_vpe *vpe)