From: Pavel Tatashin <pasha.tatashin@oracle.com>
To: steven.sistare@oracle.com, daniel.m.jordan@oracle.com,
linux@armlinux.org.uk, schwidefsky@de.ibm.com,
heiko.carstens@de.ibm.com, john.stultz@linaro.org,
sboyd@codeaurora.org, x86@kernel.org,
linux-kernel@vger.kernel.org, mingo@redhat.com,
tglx@linutronix.de, hpa@zytor.com, douly.fnst@cn.fujitsu.com,
peterz@infradead.org, prarit@redhat.com, feng.tang@intel.com,
pmladek@suse.com, gnomes@lxorguk.ukuu.org.uk,
linux-s390@vger.kernel.org, pasha.tatashin@oracle.com,
boris.ostrovsky@oracle.com, jgross@suse.com, pbonzini@redhat.com
Subject: [PATCH v14 14/25] x86/xen/time: output xen sched_clock time from 0
Date: Tue, 17 Jul 2018 22:22:00 -0400 [thread overview]
Message-ID: <20180718022211.6259-15-pasha.tatashin@oracle.com> (raw)
In-Reply-To: <20180718022211.6259-1-pasha.tatashin@oracle.com>
It is expected for sched_clock() to output data from 0, when system boots.
Add an offset xen_sched_clock_offset (similarly how it is done in other
hypervisors i.e. kvm_sched_clock_offset) to count sched_clock() from 0,
when time is first initialized.
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
---
arch/x86/xen/time.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 53bb7a8d10b5..25a780d89b7a 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -31,6 +31,8 @@
/* Xen may fire a timer up to this many ns early */
#define TIMER_SLOP 100000
+static u64 xen_sched_clock_offset __read_mostly;
+
/* Get the TSC speed from Xen */
static unsigned long xen_tsc_khz(void)
{
@@ -57,6 +59,11 @@ static u64 xen_clocksource_get_cycles(struct clocksource *cs)
return xen_clocksource_read();
}
+static u64 xen_sched_clock(void)
+{
+ return xen_clocksource_read() - xen_sched_clock_offset;
+}
+
static void xen_read_wallclock(struct timespec64 *ts)
{
struct shared_info *s = HYPERVISOR_shared_info;
@@ -367,7 +374,7 @@ void xen_timer_resume(void)
}
static const struct pv_time_ops xen_time_ops __initconst = {
- .sched_clock = xen_clocksource_read,
+ .sched_clock = xen_sched_clock,
.steal_clock = xen_steal_clock,
};
@@ -505,6 +512,7 @@ static void __init xen_time_init(void)
void __init xen_init_time_ops(void)
{
+ xen_sched_clock_offset = xen_clocksource_read();
pv_time_ops = xen_time_ops;
x86_init.timers.timer_init = xen_time_init;
--
2.18.0
next prev parent reply other threads:[~2018-07-18 2:24 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-18 2:21 [PATCH v14 00/25] Early boot time stamps Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 01/25] x86/kvmclock: Remove memblock dependency Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 02/25] x86/kvmclock: Remove page size requirement from wall_clock Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 03/25] x86/kvmclock: Decrapify kvm_register_clock() Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 04/25] x86/kvmclock: Cleanup the code Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 05/25] x86/kvmclock: Mark variables __initdata and __ro_after_init Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 06/25] x86/kvmclock: Move kvmclock vsyscall param and init to kvmclock Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 07/25] x86/kvmclock: Switch kvmclock data to a PER_CPU variable Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 08/25] x86/kvmclock: Avoid TSC recalibration Pavel Tatashin
2018-07-18 11:14 ` Paolo Bonzini
2018-07-18 13:33 ` Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 09/25] x86: text_poke() may access uninitialized struct pages Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 10/25] x86: initialize static branching early Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 11/25] x86/CPU: Call detect_nopl() only on the BSP Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 12/25] x86/tsc: redefine notsc to behave as tsc=unstable Pavel Tatashin
2018-07-18 2:21 ` [PATCH v14 13/25] x86/xen/time: initialize pv xen time in init_hypervisor_platform Pavel Tatashin
2018-07-18 2:22 ` Pavel Tatashin [this message]
2018-07-18 2:22 ` [PATCH v14 15/25] s390/time: add read_persistent_wall_and_boot_offset() Pavel Tatashin
2018-07-18 2:22 ` [PATCH v14 16/25] time: replace read_boot_clock64() with read_persistent_wall_and_boot_offset() Pavel Tatashin
2018-07-18 2:22 ` [PATCH v14 17/25] time: default boot time offset to local_clock() Pavel Tatashin
2018-07-18 2:22 ` [PATCH v14 18/25] s390/time: remove read_boot_clock64() Pavel Tatashin
2018-07-18 2:22 ` [PATCH v14 19/25] ARM/time: " Pavel Tatashin
2018-07-18 2:22 ` [PATCH v14 20/25] x86/tsc: calibrate tsc only once Pavel Tatashin
2018-07-19 5:33 ` Dou Liyang
2018-07-19 6:25 ` Thomas Gleixner
2018-07-19 6:48 ` Dou Liyang
2018-07-19 10:33 ` Peter Zijlstra
2018-07-19 11:01 ` Thomas Gleixner
2018-07-19 15:58 ` Pavel Tatashin
2018-07-19 16:19 ` Thomas Gleixner
2018-07-19 16:49 ` Pavel Tatashin
2018-07-19 18:38 ` Pavel Tatashin
2018-07-19 20:44 ` Thomas Gleixner
2018-07-19 20:46 ` Pavel Tatashin
2018-07-23 9:28 ` Alan Cox
2018-07-18 2:22 ` [PATCH v14 21/25] x86/tsc: initialize cyc2ns when tsc freq. is determined Pavel Tatashin
2018-07-18 2:22 ` [PATCH v14 22/25] x86/tsc: use tsc early Pavel Tatashin
2018-07-18 2:22 ` [PATCH v14 23/25] sched: move sched clock initialization and merge with generic clock Pavel Tatashin
2018-07-18 2:22 ` [PATCH v14 24/25] sched: early boot clock Pavel Tatashin
2018-07-19 10:39 ` Peter Zijlstra
2018-07-19 14:16 ` Pavel Tatashin
2018-07-18 2:22 ` [PATCH v14 25/25] sched: use static key for sched_clock_running Pavel Tatashin
2018-07-19 10:48 ` Peter Zijlstra
2018-07-19 14:24 ` Pavel Tatashin
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