From: Borislav Petkov <bp@alien8.de>
To: Len Brown <lenb@kernel.org>
Cc: x86@kernel.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org, Len Brown <len.brown@intel.com>
Subject: Re: [PATCH 2/2] x86: speed cpu_up by quirking cpu_init_udelay
Date: Fri, 8 May 2015 10:32:51 +0200 [thread overview]
Message-ID: <20150508083250.GB4137@pd.tnic> (raw)
In-Reply-To: <170f6f6e9ac4aa4d8ec1ed5000bee95463897337.1431066425.git.len.brown@intel.com>
On Fri, May 08, 2015 at 02:37:55AM -0400, Len Brown wrote:
> From: Len Brown <len.brown@intel.com>
>
> Modern processor familes are on a white-list to remove
> the costly cpu_init_udelay 10000. Unknown processor families
> get the traditional 10ms delay in cpu_up().
>
> This seemed more efficient than forcing modern processors
> to exhaustively search a black-list having all the old
> processor families that should have a 10ms delay.
> For not only are new processor familes infrequently added,
> the white list also allows a delay other than 0, if needed.
>
> Signed-off-by: Len Brown <len.brown@intel.com>
> ---
> arch/x86/kernel/smpboot.c | 37 +++++++++++++++++++++++++++++++++++--
> 1 file changed, 35 insertions(+), 2 deletions(-)
...
> +static void __init smp_quirk_init_udelay(void)
> +{
> + const struct x86_cpu_id *id;
> + unsigned int new_udelay;
> +
> + id = x86_match_cpu(init_udelay_ids);
> + if (id == NULL)
> + return; /* if no match, keep default */
> +
> + if (init_udelay != UDELAY_10MS_DEFAULT)
> + return; /* if cmdline changed from default, leave it alone */
> +
> + new_udelay = (unsigned long) id->driver_data;
> + pr_debug("cpu_init_udelay quirk to %d, was %d", new_udelay, init_udelay);
Can we make this printk(KERN_DEBUG please?
I'd like to be able to slap "debug" on the command line and not
recompile the kernel. And no, dyndbg="file smpboot.c +p" or whatever the
syntax is, simply doesn't scale if I want to see all debug messages from
early boot.
Thanks.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
--
next prev parent reply other threads:[~2015-05-08 8:32 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-08 6:37 [PATCH 0/2 v2] speeding up cpu_up() Len Brown
2015-05-08 6:37 ` [PATCH 1/2] x86: replace cpu_up hard-coded mdelay with variable udelay Len Brown
2015-05-08 6:37 ` [PATCH 2/2] x86: speed cpu_up by quirking cpu_init_udelay Len Brown
2015-05-08 7:51 ` Ingo Molnar
2015-05-08 8:23 ` Borislav Petkov
2015-05-08 8:32 ` Borislav Petkov [this message]
2015-05-08 18:15 ` Len Brown
2015-05-08 18:27 ` Borislav Petkov
2015-05-09 7:22 ` Ingo Molnar
2015-05-09 7:24 ` Ingo Molnar
2015-05-09 8:04 ` Borislav Petkov
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