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From: Anup Patel <anup@brainfault.org>
To: Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Palmer Dabbelt <palmer@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>
Cc: Atish Patra <atish.patra@wdc.com>,
	Christoph Hellwig <hch@infradead.org>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	Anup Patel <anup@brainfault.org>
Subject: [PATCH] clocksource: riscv_timer: Provide sched_clock
Date: Mon,  3 Dec 2018 18:05:24 +0530	[thread overview]
Message-ID: <20181203123524.11778-1-anup@brainfault.org> (raw)

Currently, we don't have a sched_clock registered for RISC-V systems.
This means Linux time keeping will use jiffies (running at HZ) as the
default sched_clock.

To avoid this, we explicity provide sched_clock using RISC-V rdtime
instruction (similar to riscv_timer clocksource).

Signed-off-by: Anup Patel <anup@brainfault.org>
---
 drivers/clocksource/riscv_timer.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/riscv_timer.c
index 084e97dc10ed..431892200a08 100644
--- a/drivers/clocksource/riscv_timer.c
+++ b/drivers/clocksource/riscv_timer.c
@@ -8,6 +8,7 @@
 #include <linux/cpu.h>
 #include <linux/delay.h>
 #include <linux/irq.h>
+#include <linux/sched_clock.h>
 #include <asm/smp.h>
 #include <asm/sbi.h>
 
@@ -49,6 +50,11 @@ static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs)
 	return get_cycles64();
 }
 
+static u64 riscv_sched_clock(void)
+{
+	return get_cycles64();
+}
+
 static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = {
 	.name		= "riscv_clocksource",
 	.rating		= 300,
@@ -97,6 +103,9 @@ static int __init riscv_timer_init_dt(struct device_node *n)
 	cs = per_cpu_ptr(&riscv_clocksource, cpuid);
 	clocksource_register_hz(cs, riscv_timebase);
 
+	sched_clock_register(riscv_sched_clock,
+			BITS_PER_LONG, riscv_timebase);
+
 	error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING,
 			 "clockevents/riscv/timer:starting",
 			 riscv_timer_starting_cpu, riscv_timer_dying_cpu);
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: Anup Patel <anup@brainfault.org>
To: Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Palmer Dabbelt <palmer@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>
Cc: Christoph Hellwig <hch@infradead.org>,
	Atish Patra <atish.patra@wdc.com>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	Anup Patel <anup@brainfault.org>
Subject: [PATCH] clocksource: riscv_timer: Provide sched_clock
Date: Mon,  3 Dec 2018 18:05:24 +0530	[thread overview]
Message-ID: <20181203123524.11778-1-anup@brainfault.org> (raw)

Currently, we don't have a sched_clock registered for RISC-V systems.
This means Linux time keeping will use jiffies (running at HZ) as the
default sched_clock.

To avoid this, we explicity provide sched_clock using RISC-V rdtime
instruction (similar to riscv_timer clocksource).

Signed-off-by: Anup Patel <anup@brainfault.org>
---
 drivers/clocksource/riscv_timer.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/riscv_timer.c
index 084e97dc10ed..431892200a08 100644
--- a/drivers/clocksource/riscv_timer.c
+++ b/drivers/clocksource/riscv_timer.c
@@ -8,6 +8,7 @@
 #include <linux/cpu.h>
 #include <linux/delay.h>
 #include <linux/irq.h>
+#include <linux/sched_clock.h>
 #include <asm/smp.h>
 #include <asm/sbi.h>
 
@@ -49,6 +50,11 @@ static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs)
 	return get_cycles64();
 }
 
+static u64 riscv_sched_clock(void)
+{
+	return get_cycles64();
+}
+
 static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = {
 	.name		= "riscv_clocksource",
 	.rating		= 300,
@@ -97,6 +103,9 @@ static int __init riscv_timer_init_dt(struct device_node *n)
 	cs = per_cpu_ptr(&riscv_clocksource, cpuid);
 	clocksource_register_hz(cs, riscv_timebase);
 
+	sched_clock_register(riscv_sched_clock,
+			BITS_PER_LONG, riscv_timebase);
+
 	error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING,
 			 "clockevents/riscv/timer:starting",
 			 riscv_timer_starting_cpu, riscv_timer_dying_cpu);
-- 
2.17.1


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             reply	other threads:[~2018-12-03 12:35 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-03 12:35 Anup Patel [this message]
2018-12-03 12:35 ` [PATCH] clocksource: riscv_timer: Provide sched_clock Anup Patel
2018-12-03 12:59 ` Daniel Lezcano
2018-12-03 12:59   ` Daniel Lezcano
2018-12-03 14:50   ` Anup Patel
2018-12-03 14:50     ` Anup Patel
2018-12-03 14:53     ` Daniel Lezcano
2018-12-03 14:53       ` Daniel Lezcano
2018-12-06 20:32 ` Palmer Dabbelt
2018-12-06 20:32   ` Palmer Dabbelt
2018-12-07  2:27   ` Anup Patel
2018-12-07  2:27     ` Anup Patel

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