linux-kernel - Re: [PATCH] x86: Align jump targets to 1 byte boundaries

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Message-ID: <20150410131929.GE28074@pd.tnic>
Date:	Fri, 10 Apr 2015 15:19:29 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Jason Low <jason.low2@...com>,
	Peter Zijlstra <peterz@...radead.org>,
	Davidlohr Bueso <dave@...olabs.net>,
	Tim Chen <tim.c.chen@...ux.intel.com>,
	Aswin Chandramouleeswaran <aswin@...com>,
	LKML <linux-kernel@...r.kernel.org>,
	Andy Lutomirski <luto@...capital.net>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Brian Gerst <brgerst@...il.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [PATCH] x86: Align jump targets to 1 byte boundaries

On Fri, Apr 10, 2015 at 02:08:46PM +0200, Ingo Molnar wrote:
> Now, the usual justification for jump target alignment is the 
> following: with 16 byte instruction-cache cacheline sizes, if a 

You mean 64 bytes?

Cacheline size on modern x86 is 64 bytes. The 16 alignment is probably
some branch predictor stride thing.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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