[PATCH] clocksource/drivers/riscv: Increase the clock source rating
From: Samuel Holland
Date: Tue Dec 27 2022 - 19:44:58 EST
RISC-V provides an architectural clock source via the time CSR. This
clock source exposes a 64-bit counter synchronized across all CPUs.
Because it is accessed using a CSR, it is much more efficient to read
than MMIO clock sources. For example, on the Allwinner D1, reading the
sun4i timer in a loop takes 131 cycles/iteration, while reading the
RISC-V time CSR takes only 5 cycles/iteration.
Adjust the RISC-V clock source rating so it is preferred over the
various platform-specific MMIO clock sources.
Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
---
drivers/clocksource/timer-riscv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index a0d66fabf073..55dad7965f43 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -73,7 +73,7 @@ static u64 notrace riscv_sched_clock(void)
static struct clocksource riscv_clocksource = {
.name = "riscv_clocksource",
- .rating = 300,
+ .rating = 400,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.read = riscv_clocksource_rdtime,
--
2.37.4