From: Thomas Gleixner <tglx@linutronix.de>
To: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
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, hpa@zytor.com,
douly.fnst@cn.fujitsu.com, prarit@redhat.com,
feng.tang@intel.com, pmladek@suse.com,
gnomes@lxorguk.ukuu.org.uk, linux-s390@vger.kernel.org,
boris.ostrovsky@oracle.com, jgross@suse.com, pbonzini@redhat.com
Subject: Re: [PATCH v14 20/25] x86/tsc: calibrate tsc only once
Date: Thu, 19 Jul 2018 18:19:33 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1807191817080.1693@nanos.tec.linutronix.de> (raw)
In-Reply-To: <4295075b-8a0f-1723-2e80-1bbd2f038846@oracle.com>
On Thu, 19 Jul 2018, Pavel Tatashin wrote:
> On 07/19/2018 07:01 AM, Thomas Gleixner wrote:
>
> And hpet_pmtime_calibrate_cpu() contains all the hpet/pmtime stuff.
>
> However, when cpu_khz = x86_platform.calibrate_cpu() is called the first
> time, we still call hpet_pmtime_calibrate_cpu() from
> native_calibrate_cpu(). We cannot simply split native_calibrate_cpu()
> into two independent functions because it is also called from
> recalibrate_cpu_khz().
> So, the question is how to enforce that the first time we do not call hpet/pmtime?
>
> 1. Use a new global variable? Kind of ugly.
> 2. Use system_state == SYSTEM_BOOTING ? Ugly, and probably not very safe.
Both are horrible.
So create two functions. native_...early..() and native....(). The early
one does not contain the hpet/pmtimer stuff and it replaces the ops.pointer
with the late one which contains all of it.
Hmm?
Thanks,
tglx
next prev parent reply other threads:[~2018-07-19 16:20 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 ` [PATCH v14 14/25] x86/xen/time: output xen sched_clock time from 0 Pavel Tatashin
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 [this message]
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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