From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: 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,
peterz@infradead.org, tglx@linutronix.de, hpa@zytor.com,
douly.fnst@cn.fujitsu.com
Subject: Re: [PATCH v6 1/4] sched/clock: interface to allow timestamps early in boot
Date: Wed, 27 Sep 2017 15:45:06 +0100 [thread overview]
Message-ID: <20170927144506.GU20805@n2100.armlinux.org.uk> (raw)
In-Reply-To: <1504116205-355281-2-git-send-email-pasha.tatashin@oracle.com>
On Wed, Aug 30, 2017 at 02:03:22PM -0400, Pavel Tatashin wrote:
> In Linux printk() can output timestamps next to every line. This is very
> useful for tracking regressions, and finding places that can be optimized.
> However, the timestamps are available only later in boot. On smaller
> machines it is insignificant amount of time, but on larger it can be many
> seconds or even minutes into the boot process.
The sched_clock work I did for ARM could be setup really early at boot,
from setup_arch(). I tried to encourage platforms to do that, but all
my encouragement fell on deaf ears - most people setup the sched_clock
source along side the time initialisation on ARM.
I don't think we need yet another "early" mechanism to solve this problem,
we just need people to use the existing mechanism to register their
sched_clock implementation earlier.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
According to speedtest.net: 8.21Mbps down 510kbps up
next prev parent reply other threads:[~2017-09-27 14:45 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-30 18:03 [PATCH v6 0/4] Early boot time stamps for x86 Pavel Tatashin
2017-08-30 18:03 ` [PATCH v6 1/4] sched/clock: interface to allow timestamps early in boot Pavel Tatashin
2017-09-27 12:58 ` Peter Zijlstra
2017-09-27 13:10 ` Peter Zijlstra
2017-09-27 13:16 ` Pasha Tatashin
2017-09-27 13:52 ` Dou Liyang
2017-09-27 17:13 ` Pasha Tatashin
2017-09-27 18:05 ` Peter Zijlstra
2017-09-27 18:09 ` Peter Zijlstra
2017-09-28 10:03 ` Dou Liyang
2017-09-28 11:58 ` Peter Zijlstra
2017-09-28 12:12 ` Thomas Gleixner
2017-09-28 13:11 ` Pasha Tatashin
2017-09-29 15:00 ` Dou Liyang
2017-10-18 10:01 ` Dou Liyang
2017-10-18 13:38 ` Pavel Tatashin
2017-10-09 16:34 ` Pavel Tatashin
2017-10-18 21:01 ` Thomas Gleixner
2017-09-27 14:45 ` Russell King - ARM Linux [this message]
2017-09-27 17:10 ` Pasha Tatashin
2017-09-27 18:11 ` Peter Zijlstra
2017-08-30 18:03 ` [PATCH v6 2/4] time: sync read_boot_clock64() with persistent clock Pavel Tatashin
2017-08-30 18:03 ` [PATCH v6 3/4] x86/time: read_boot_clock64() implementation Pavel Tatashin
2017-08-30 18:03 ` [PATCH v6 4/4] x86/tsc: use tsc early Pavel Tatashin
[not found] ` <CALBSrqBKsojGGpe85GOg7jda-SJHLrR=pS-Pg-xa0SUg7j3OQA@mail.gmail.com>
2017-08-30 21:21 ` Fenghua Yu
2017-08-30 21:32 ` Pasha Tatashin
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