[PATCH v2 18/20] mips: csrc-r4k: Decrease r4k-clocksource rating if CPU_FREQ enabled

Sergey.Semin
2020-05-06T17:45:04Z

From: Serge Semin <Sergey.Semin@baikalelectronics.ru>

Commit 07d69579e7fe ("MIPS: Don't register r4k sched clock when
CPUFREQ enabled") disabled the r4k-clock usage for scheduler ticks
counting due to the scheduler being non-tolerant for unstable
clocks sources. For the same reason the clock should be used
in the system clocksource framework only as a last resort if CPU
frequency may change.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-pm@vger.kernel.org
Cc: devicetree@vger.kernel.org
---
arch/mips/kernel/csrc-r4k.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/mips/kernel/csrc-r4k.c b/arch/mips/kernel/csrc-r4k.c
index 437dda64fd7a..d81fb374f477 100644
--- a/arch/mips/kernel/csrc-r4k.c
+++ b/arch/mips/kernel/csrc-r4k.c
@@ -71,7 +71,11 @@ int __init init_r4k_clocksource(void)
return -ENXIO;

/* Calculate a somewhat reasonable rating value */
+#ifndef CONFIG_CPU_FREQ
clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
+#else
+ clocksource_mips.rating = 99;
+#endif

/*
* R2 onwards makes the count accessible to user mode so it can be used
--
2.25.1