From: Ingo Molnar <mingo@kernel.org>
To: "Brown, Len" <len.brown@intel.com>
Cc: Len Brown <lenb@kernel.org>, "x86@kernel.org" <x86@kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 1/1] x86: replace cpu_up hard-coded mdelay with variable
Date: Mon, 20 Apr 2015 19:45:44 +0200 [thread overview]
Message-ID: <20150420174544.GA18931@gmail.com> (raw)
In-Reply-To: <1A7043D5F58CCB44A599DFD55ED4C94846861500@fmsmsx115.amr.corp.intel.com>
* Brown, Len <len.brown@intel.com> wrote:
> > What's the cutoff for 'modern hardware' - which CPUs stopped requiring
> > the delay?
>
> This is the topic of ongoing research, and I'm not ready to send
> the patch setting a new default until I've heard back from a few more HW people.
>
> Every system I've tested appears to work with delay 0.
> Were I to guess, I'd venture that every
> system that runs an X86_64 kernel might count as "modern" -- even
> the 2005 AMD Turion laptop I've got in the bone pile.
Could we use the apic version as a cutoff perhaps?
It would be nice to 'automatically' include modern 32-bit x86 systems
as well.
Any failure here would be relatively easy to bisect to, so we might as
well guess a bit and refine the quirk condition if needed?
Thanks,
Ingo
next prev parent reply other threads:[~2015-04-20 17:45 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-19 0:53 [PATCH 0/1] speeding up cpu_up() Len Brown
2015-04-19 0:53 ` [PATCH 1/1] x86: replace cpu_up hard-coded mdelay with variable Len Brown
2015-04-20 7:13 ` Ingo Molnar
2015-04-20 12:37 ` Brown, Len
2015-04-20 17:45 ` Ingo Molnar [this message]
2015-04-22 5:40 ` Paul Gortmaker
2015-04-22 6:07 ` Ingo Molnar
2015-05-01 21:02 ` Len Brown
2015-04-20 7:15 ` [PATCH 0/1] speeding up cpu_up() Ingo Molnar
2015-05-01 21:42 ` Len Brown
2015-05-01 22:47 ` Borislav Petkov
2015-05-02 0:42 ` Aravind Gopalakrishnan
2015-05-03 16:13 ` Aravind Gopalakrishnan
2015-05-04 22:45 ` Aravind Gopalakrishnan
2015-05-05 7:15 ` Borislav Petkov
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