From: tip-bot for Pavel Tatashin <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: pasha.tatashin@oracle.com, linux-kernel@vger.kernel.org,
tglx@linutronix.de, hpa@zytor.com, mingo@kernel.org
Subject: [tip:x86/timers] x86/tsc: Calibrate tsc only once
Date: Thu, 19 Jul 2018 15:31:17 -0700 [thread overview]
Message-ID: <tip-cf7a63ef4e0203f6f33284c69e8188d91422de83@git.kernel.org> (raw)
In-Reply-To: <20180719205545.16512-20-pasha.tatashin@oracle.com>
Commit-ID: cf7a63ef4e0203f6f33284c69e8188d91422de83
Gitweb: https://git.kernel.org/tip/cf7a63ef4e0203f6f33284c69e8188d91422de83
Author: Pavel Tatashin <pasha.tatashin@oracle.com>
AuthorDate: Thu, 19 Jul 2018 16:55:38 -0400
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 20 Jul 2018 00:02:42 +0200
x86/tsc: Calibrate tsc only once
During boot tsc is calibrated twice: once in tsc_early_delay_calibrate(),
and the second time in tsc_init().
Rename tsc_early_delay_calibrate() to tsc_early_init(), and rework it so
the calibration is done only early, and make tsc_init() to use the values
already determined in tsc_early_init().
Sometimes it is not possible to determine tsc early, as the subsystem that
is required is not yet initialized, in such case try again later in
tsc_init().
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: steven.sistare@oracle.com
Cc: daniel.m.jordan@oracle.com
Cc: linux@armlinux.org.uk
Cc: schwidefsky@de.ibm.com
Cc: heiko.carstens@de.ibm.com
Cc: john.stultz@linaro.org
Cc: sboyd@codeaurora.org
Cc: hpa@zytor.com
Cc: douly.fnst@cn.fujitsu.com
Cc: peterz@infradead.org
Cc: prarit@redhat.com
Cc: feng.tang@intel.com
Cc: pmladek@suse.com
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: linux-s390@vger.kernel.org
Cc: boris.ostrovsky@oracle.com
Cc: jgross@suse.com
Cc: pbonzini@redhat.com
Link: https://lkml.kernel.org/r/20180719205545.16512-20-pasha.tatashin@oracle.com
---
arch/x86/include/asm/tsc.h | 2 +-
arch/x86/kernel/setup.c | 2 +-
arch/x86/kernel/tsc.c | 87 +++++++++++++++++++++++++---------------------
3 files changed, 49 insertions(+), 42 deletions(-)
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 2701d221583a..c4368ff73652 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -33,7 +33,7 @@ static inline cycles_t get_cycles(void)
extern struct system_counterval_t convert_art_to_tsc(u64 art);
extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns);
-extern void tsc_early_delay_calibrate(void);
+extern void tsc_early_init(void);
extern void tsc_init(void);
extern void mark_tsc_unstable(char *reason);
extern int unsynchronized_tsc(void);
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 7490de925a81..5d32c55aeb8b 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1014,6 +1014,7 @@ void __init setup_arch(char **cmdline_p)
*/
init_hypervisor_platform();
+ tsc_early_init();
x86_init.resources.probe_roms();
/* after parse_early_param, so could debug it */
@@ -1199,7 +1200,6 @@ void __init setup_arch(char **cmdline_p)
memblock_find_dma_reserve();
- tsc_early_delay_calibrate();
if (!early_xdbc_setup_hardware())
early_xdbc_register_console();
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 186395041725..4cab2236169e 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -33,6 +33,8 @@ EXPORT_SYMBOL(cpu_khz);
unsigned int __read_mostly tsc_khz;
EXPORT_SYMBOL(tsc_khz);
+#define KHZ 1000
+
/*
* TSC can be unstable due to cpufreq or due to unsynced TSCs
*/
@@ -1335,34 +1337,10 @@ unreg:
*/
device_initcall(init_tsc_clocksource);
-void __init tsc_early_delay_calibrate(void)
-{
- unsigned long lpj;
-
- if (!boot_cpu_has(X86_FEATURE_TSC))
- return;
-
- cpu_khz = x86_platform.calibrate_cpu();
- tsc_khz = x86_platform.calibrate_tsc();
-
- tsc_khz = tsc_khz ? : cpu_khz;
- if (!tsc_khz)
- return;
-
- lpj = tsc_khz * 1000;
- do_div(lpj, HZ);
- loops_per_jiffy = lpj;
-}
-
-void __init tsc_init(void)
+static bool __init determine_cpu_tsc_frequencies(void)
{
- u64 lpj, cyc;
- int cpu;
-
- if (!boot_cpu_has(X86_FEATURE_TSC)) {
- setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER);
- return;
- }
+ /* Make sure that cpu and tsc are not already calibrated */
+ WARN_ON(cpu_khz || tsc_khz);
cpu_khz = x86_platform.calibrate_cpu();
tsc_khz = x86_platform.calibrate_tsc();
@@ -1377,20 +1355,52 @@ void __init tsc_init(void)
else if (abs(cpu_khz - tsc_khz) * 10 > tsc_khz)
cpu_khz = tsc_khz;
- if (!tsc_khz) {
- mark_tsc_unstable("could not calculate TSC khz");
- setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER);
- return;
- }
+ if (tsc_khz == 0)
+ return false;
pr_info("Detected %lu.%03lu MHz processor\n",
- (unsigned long)cpu_khz / 1000,
- (unsigned long)cpu_khz % 1000);
+ (unsigned long)cpu_khz / KHZ,
+ (unsigned long)cpu_khz % KHZ);
if (cpu_khz != tsc_khz) {
pr_info("Detected %lu.%03lu MHz TSC",
- (unsigned long)tsc_khz / 1000,
- (unsigned long)tsc_khz % 1000);
+ (unsigned long)tsc_khz / KHZ,
+ (unsigned long)tsc_khz % KHZ);
+ }
+ return true;
+}
+
+static unsigned long __init get_loops_per_jiffy(void)
+{
+ unsigned long lpj = tsc_khz * KHZ;
+
+ do_div(lpj, HZ);
+ return lpj;
+}
+
+void __init tsc_early_init(void)
+{
+ if (!boot_cpu_has(X86_FEATURE_TSC))
+ return;
+ if (!determine_cpu_tsc_frequencies())
+ return;
+ loops_per_jiffy = get_loops_per_jiffy();
+}
+
+void __init tsc_init(void)
+{
+ if (!boot_cpu_has(X86_FEATURE_TSC)) {
+ setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER);
+ return;
+ }
+
+ if (!tsc_khz) {
+ /* We failed to determine frequencies earlier, try again */
+ if (!determine_cpu_tsc_frequencies()) {
+ mark_tsc_unstable("could not calculate TSC khz");
+ setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER);
+ return;
+ }
}
/* Sanitize TSC ADJUST before cyc2ns gets initialized */
@@ -1413,10 +1423,7 @@ void __init tsc_init(void)
if (!no_sched_irq_time)
enable_sched_clock_irqtime();
- lpj = ((u64)tsc_khz * 1000);
- do_div(lpj, HZ);
- lpj_fine = lpj;
-
+ lpj_fine = get_loops_per_jiffy();
use_tsc_delay();
check_system_tsc_reliable();
next prev parent reply other threads:[~2018-07-19 22:31 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-19 20:55 [PATCH v15 00/26] Early boot time stamps Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 01/26] x86/kvmclock: Remove memblock dependency Pavel Tatashin
2018-07-19 22:21 ` [tip:x86/timers] " tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 02/26] x86/kvmclock: Remove page size requirement from wall_clock Pavel Tatashin
2018-07-19 22:22 ` [tip:x86/timers] " tip-bot for Thomas Gleixner
2018-07-19 20:55 ` [PATCH v15 03/26] x86/kvmclock: Decrapify kvm_register_clock() Pavel Tatashin
2018-07-19 22:23 ` [tip:x86/timers] " tip-bot for Thomas Gleixner
2018-07-19 20:55 ` [PATCH v15 04/26] x86/kvmclock: Cleanup the code Pavel Tatashin
2018-07-19 22:23 ` [tip:x86/timers] " tip-bot for Thomas Gleixner
2018-07-19 20:55 ` [PATCH v15 05/26] x86/kvmclock: Mark variables __initdata and __ro_after_init Pavel Tatashin
2018-07-19 22:24 ` [tip:x86/timers] " tip-bot for Thomas Gleixner
2018-07-19 20:55 ` [PATCH v15 06/26] x86/kvmclock: Move kvmclock vsyscall param and init to kvmclock Pavel Tatashin
2018-07-19 22:24 ` [tip:x86/timers] " tip-bot for Thomas Gleixner
2018-07-19 20:55 ` [PATCH v15 07/26] x86/kvmclock: Switch kvmclock data to a PER_CPU variable Pavel Tatashin
2018-07-19 22:25 ` [tip:x86/timers] " tip-bot for Thomas Gleixner
2018-07-19 20:55 ` [PATCH v15 08/26] x86: text_poke() may access uninitialized struct pages Pavel Tatashin
2018-07-19 22:25 ` [tip:x86/timers] x86/alternatives, jumplabel: Use text_poke_early() before mm_init() tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 09/26] x86: initialize static branching early Pavel Tatashin
2018-07-19 22:26 ` [tip:x86/timers] x86/jump_label: Initialize " tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 10/26] x86/CPU: Call detect_nopl() only on the BSP Pavel Tatashin
2018-07-19 22:26 ` [tip:x86/timers] " tip-bot for Borislav Petkov
2018-07-19 20:55 ` [PATCH v15 11/26] x86/tsc: redefine notsc to behave as tsc=unstable Pavel Tatashin
2018-07-19 22:27 ` [tip:x86/timers] x86/tsc: Redefine " tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 12/26] x86/xen/time: initialize pv xen time in init_hypervisor_platform Pavel Tatashin
2018-07-19 22:27 ` [tip:x86/timers] x86/xen/time: Initialize pv xen time in init_hypervisor_platform() tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 13/26] x86/xen/time: output xen sched_clock time from 0 Pavel Tatashin
2018-07-19 22:28 ` [tip:x86/timers] x86/xen/time: Output " tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 14/26] s390/time: add read_persistent_wall_and_boot_offset() Pavel Tatashin
2018-07-19 22:28 ` [tip:x86/timers] s390/time: Add read_persistent_wall_and_boot_offset() tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 15/26] time: replace read_boot_clock64() with read_persistent_wall_and_boot_offset() Pavel Tatashin
2018-07-19 22:29 ` [tip:x86/timers] timekeeping: Replace " tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 16/26] time: default boot time offset to local_clock() Pavel Tatashin
2018-07-19 22:29 ` [tip:x86/timers] timekeeping: Default " tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 17/26] s390/time: remove read_boot_clock64() Pavel Tatashin
2018-07-19 22:30 ` [tip:x86/timers] s390/time: Remove read_boot_clock64() tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 18/26] ARM/time: remove read_boot_clock64() Pavel Tatashin
2018-07-19 22:30 ` [tip:x86/timers] ARM/time: Remove read_boot_clock64() tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 19/26] x86/tsc: calibrate tsc only once Pavel Tatashin
2018-07-19 22:31 ` tip-bot for Pavel Tatashin [this message]
2018-07-19 20:55 ` [PATCH v15 20/26] x86/tsc: initialize cyc2ns when tsc freq. is determined Pavel Tatashin
2018-07-19 22:31 ` [tip:x86/timers] x86/tsc: Initialize cyc2ns when tsc frequency " tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 21/26] x86/tsc: use tsc early Pavel Tatashin
2018-07-19 22:32 ` [tip:x86/timers] x86/tsc: Use TSC as sched clock early tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 22/26] sched: move sched clock initialization and merge with generic clock Pavel Tatashin
2018-07-19 22:32 ` [tip:x86/timers] sched/clock: Move " tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 23/26] sched: early boot clock Pavel Tatashin
2018-07-19 22:33 ` [tip:x86/timers] sched/clock: Enable sched clock early tip-bot for Pavel Tatashin
2018-07-24 19:52 ` Guenter Roeck
2018-07-24 20:22 ` Pavel Tatashin
2018-07-25 0:36 ` Pavel Tatashin
2018-07-25 1:24 ` Guenter Roeck
2018-07-25 2:05 ` Pavel Tatashin
2018-07-25 2:41 ` Pavel Tatashin
2018-07-30 12:36 ` Peter Zijlstra
2018-07-30 13:44 ` Pavel Tatashin
2018-07-20 8:09 ` [PATCH v15 23/26] sched: early boot clock Peter Zijlstra
2018-07-20 10:00 ` [tip:x86/timers] sched/clock: Close a hole in sched_clock_init() tip-bot for Peter Zijlstra
2018-11-06 5:42 ` [PATCH v15 23/26] sched: early boot clock Dominique Martinet
2018-11-06 11:35 ` Steven Sistare
2019-01-02 20:20 ` Salvatore Bonaccorso
2019-01-03 21:28 ` Pavel Tatashin
2019-01-03 23:43 ` Dominique Martinet
2019-01-07 18:17 ` Pavel Tatashin
2019-01-07 23:48 ` Dominique Martinet
2019-01-08 1:04 ` Pavel Tatashin
2019-01-08 1:09 ` Dominique Martinet
2019-01-26 2:04 ` Jon DeVree
2019-01-26 16:11 ` Pavel Tatashin
2019-01-04 7:30 ` [PATCH v15 23/26] sched: early boot clock (was Re: Bug#918036: linux: uptime after reboot wrong (kvm-clock related?)) Thorsten Glaser
2018-07-19 20:55 ` [PATCH v15 24/26] sched: use static key for sched_clock_running Pavel Tatashin
2018-07-19 22:33 ` [tip:x86/timers] sched/clock: Use " tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 25/26] x86/tsc: split native_calibrate_cpu() into early and late parts Pavel Tatashin
2018-07-19 22:34 ` [tip:x86/timers] x86/tsc: Split " tip-bot for Pavel Tatashin
2018-07-19 20:55 ` [PATCH v15 26/26] x86/tsc: use tsc_calibrate_cpu_early and pit_hpet_ptimer_calibrate_cpu Pavel Tatashin
2018-07-19 22:35 ` [tip:x86/timers] x86/tsc: Make use of tsc_calibrate_cpu_early() tip-bot for Pavel Tatashin
2018-07-19 22:34 ` [PATCH v15 00/26] Early boot time stamps Thomas Gleixner
[not found] <154644530361.2390.18185252504260044930.reportbug@ci-busyapps.lan.tarent.de>
[not found] ` <20190102163939.GB13145@eldamar.local>
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