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From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Frediano Ziglio <frediano.ziglio@cloud.com>
Cc: xen-devel@lists.xenproject.org, Jan Beulich <jbeulich@suse.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>, Wei Liu <wl@xen.org>
Subject: Re: [PATCH v2] Reduce assembly code size of exception entry points
Date: Wed, 14 Feb 2024 16:02:26 +0100	[thread overview]
Message-ID: <ZczWAg-zmoLXiWAr@macbook> (raw)
In-Reply-To: <20240214103558.13655-1-frediano.ziglio@cloud.com>

On Wed, Feb 14, 2024 at 10:35:58AM +0000, Frediano Ziglio wrote:
> We just pushed a 8-bytes zero and exception constants are
> small so we can just write a single byte saving 3 bytes for
> instruction.
> With ENDBR64 this reduces the size of many entry points from 32 to
> 16 bytes (due to alignment).
> Similar code is already used in autogen_stubs.

Will using movb instead of movl have any performance impact?  I don't
think we should trade speed for code size, so this needs to be
mentioned in the commit message.

Thanks, Roger.


  parent reply	other threads:[~2024-02-14 15:02 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-14 10:35 [PATCH v2] Reduce assembly code size of exception entry points Frediano Ziglio
2024-02-14 13:56 ` Jan Beulich
2024-02-14 14:20 ` Jan Beulich
2024-02-14 15:02 ` Roger Pau Monné [this message]
2024-02-14 15:08   ` Jan Beulich
2024-02-14 15:29     ` Roger Pau Monné
2024-02-14 15:53       ` Andrew Cooper
2024-02-14 16:05         ` Roger Pau Monné

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