From: "Luc, Piotr" <Piotr.Luc@intel.com>
To: "hpa@zytor.com" <hpa@zytor.com>, "bp@alien8.de" <bp@alien8.de>
Cc: "mingo@kernel.org" <mingo@kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"linux-tip-commits@vger.kernel.org"
<linux-tip-commits@vger.kernel.org>,
"jpoimboe@redhat.com" <jpoimboe@redhat.com>,
"brgerst@gmail.com" <brgerst@gmail.com>,
"luto@kernel.org" <luto@kernel.org>,
"Hansen, Dave" <dave.hansen@intel.com>,
"dvlasenk@redhat.com" <dvlasenk@redhat.com>
Subject: Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS features
Date: Mon, 17 Oct 2016 09:55:07 +0000 [thread overview]
Message-ID: <1476697859.27884.21.camel@intel.com> (raw)
In-Reply-To: <20161016224258.e2jen3qkoo3m6qd7@pd.tnic>
On Mon, 2016-10-17 at 00:42 +0200, Borislav Petkov wrote:
> On Sun, Oct 16, 2016 at 11:42:26AM -0700, hpa@zytor.com wrote:
> >
> > It's needlessly adding complexity for no reason, at least for the
>
> What complexity? The init_scattered_cpuid_features() version is a
> trivial patch in comparison to the current version.
>
> >
> > leaves that are going to add bits over time.
>
> Sure, except they don't get added or we don't need them or whatever,
> and
> we end up with only a small number of bits actually being used.
>
> I don't mind moving them to x86_capability later, when a high
> percentage
> of the respective leaf is actually being used but not for a couple of
> bits. That's just waste.
>
> >
> > The x86_capability array is not an expensive resource.
>
> 0.1% here, 0.1% there, the creeping bloat thing.
>
> And again, the init_scattered_cpuid_features() hunk is much smaller.
>
I agree, the scattered solution reduces data segment footprint in case
many cores.
Regards,
Piotr
next prev parent reply other threads:[~2016-10-17 9:55 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-12 17:57 [PATCH] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS features Piotr Luc
2016-10-16 11:21 ` [tip:x86/urgent] " tip-bot for Piotr Luc
2016-10-16 14:22 ` Borislav Petkov
2016-10-16 16:02 ` hpa
2016-10-16 16:35 ` Borislav Petkov
2016-10-16 18:42 ` hpa
2016-10-16 22:42 ` Borislav Petkov
2016-10-17 9:55 ` Luc, Piotr [this message]
2016-10-17 7:55 ` Thomas Gleixner
2016-10-17 8:20 ` Luc, Piotr
2016-10-17 8:47 ` Ingo Molnar
2016-10-17 9:53 ` Luc, Piotr
2016-10-17 9:54 ` Thomas Gleixner
2016-10-17 15:03 ` [PATCH v2] " Piotr Luc
2016-10-18 13:00 ` [v2] " Luc, Piotr
2016-10-18 13:08 ` Ingo Molnar
2016-10-18 15:01 ` [PATCH v3] " Piotr Luc
2016-10-19 15:43 ` [tip:x86/urgent] " tip-bot for Piotr Luc
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