Date: Thu, 7 May 2015 12:59:00 +0200
From: Borislav Petkov <bp@alien8.de>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo2.kernel.org@gmail.com>, linux-kernel@vger.kernel.org,
        Andy Lutomirski <luto@amacapital.net>,
        Fenghua Yu <fenghua.yu@intel.com>, "H. Peter Anvin" <hpa@zytor.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 084/208] x86/fpu: Rename xsave.header::xstate_bv to
 'xfeatures'
Message-ID: <20150507105859.GH6859@pd.tnic>
References: <1430848300-27877-1-git-send-email-mingo@kernel.org>
 <1430848300-27877-6-git-send-email-mingo@kernel.org>
 <554904A6.8040503@linux.intel.com>
 <20150505181613.GA28562@gmail.com>
 <55490B1F.3080409@linux.intel.com>
 <20150506061603.GA13720@gmail.com>
 <554A5D23.2030405@linux.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <554A5D23.2030405@linux.intel.com>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 874
Lines: 28

On Wed, May 06, 2015 at 11:27:47AM -0700, Dave Hansen wrote:
> But we'd need to get to a point where we are calling 'xsaves' with a
> Requested Feature BitMask (aka RFBM[]) that had holes in it.  As it
> stands today, we always call it with RFBM=-1 and so we always have
> XCOMP_BV = XCR0.
> 
> We'd need to determine which fields are in the init state before we do
> an xsaves.

Btw, do we have any perf data as to the improvement the compacted
variant brings?

I mean, it means a bunch of jumping through hoops in SW but is it worth
it?

Thanks.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/