From: Ingo Molnar <mingo@elte.hu>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Typo in x86 apic.c with DIVISOR setup
Date: Fri, 10 Oct 2008 11:01:00 +0200 [thread overview]
Message-ID: <20081010090100.GC319@elte.hu> (raw)
In-Reply-To: <aa79d98a0810092239p32153776qd0cda47e54929545@mail.gmail.com>
* Cyrill Gorcunov <gorcunov@gmail.com> wrote:
> Ah, it was CONFG who is guilty :) This is true indeed, thanks!
yeah.
> But here is not the same
>
> apic_write(APIC_TDCR,
> (tmp_value & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE)) |
> - APIC_TDR_DIV_16);
> + APIC_TDR_DIV);
>
> On x86_64 it will be 1 now but we've used 16 for a long time in
> purpose to slowdown processor's bus CLKs from APIC point of view. So I
> don't think it's good idea to change it now. If we start using divisor
> 1 today -- it would work for some time 'till processor bus raised to
> the some speed when we'll get counter underflow before calibration
> finished.
>
> So could you please split the patch into two:
> 1) Plain CONFG typo fix (which is completely Ack'ed)
> 2) APIC divisor patch (which I'm not sure if we've to touch)
okay, since we typoed that CONFG thing (sidenote: we really need a
.config flag that will start a grep that fails the build if there's a
non-existent CONFIG option anywhere in the tree), we basically tested
the divisor of 16 on a wide range of boxes.
So .. how about just standardizing on the divisor of 16 on both 32-bit
and 64-bit?
Ingo
next prev parent reply other threads:[~2008-10-10 9:01 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-10 0:22 [PATCH] Typo in x86 apic.c with DIVISOR setup Venki Pallipadi
2008-10-10 4:38 ` Cyrill Gorcunov
2008-10-10 5:10 ` Pallipadi, Venkatesh
2008-10-10 5:39 ` Cyrill Gorcunov
2008-10-10 9:01 ` Ingo Molnar [this message]
2008-10-10 11:14 ` Cyrill Gorcunov
2008-10-10 11:15 ` Maciej W. Rozycki
2008-10-10 11:16 ` Cyrill Gorcunov
2008-10-10 11:24 ` Maciej W. Rozycki
2008-10-10 11:56 ` Ingo Molnar
2008-10-10 12:38 ` Cyrill Gorcunov
2008-10-10 14:45 ` Ingo Molnar
2008-10-10 12:26 ` Cyrill Gorcunov
2008-10-10 16:01 ` Pallipadi, Venkatesh
2008-10-10 16:29 ` Maciej W. Rozycki
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