Date: Mon, 21 Oct 2013 11:28:34 -0700 From: John-Mark Gurney <jmg@funkthat.com> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: Andre Oppermann <andre@freebsd.org>, Mark R V Murray <mark@grondar.org>, freebsd-arch@freebsd.org Subject: Re: always load aesni or load it when cpu supports it Message-ID: <20131021182834.GX56872@funkthat.com> In-Reply-To: <37693.1382379728@critter.freebsd.dk> References: <20131020070022.GP56872@funkthat.com> <423D921D-6CE5-49D9-BCED-AB14EB236800@grondar.org> <20131020161634.GQ56872@funkthat.com> <5264F074.4010607@freebsd.org> <20131021164034.GU56872@funkthat.com> <37693.1382379728@critter.freebsd.dk>
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Poul-Henning Kamp wrote this message on Mon, Oct 21, 2013 at 18:22 +0000:
> In message <20131021164034.GU56872@funkthat.com>, John-Mark Gurney writes:
>
> >The choice of 32 blocks (512 bytes) was arbitrary, but chosen because
> >it is a disk sector size... If you're doing that much AES, on a slower
> >machine, you'll probably want to use an accelerator...
>
> I'd say it is both arbitrary and pointless.
>
> Logical "disk-sectors" under both GBDE and GELI can be any size
> (think RAID-5 stripe) and consumer harddisks have 4K sectors these days.
>
> Why do you fee a limit is necessary ?
If you're on a slow system (embeded x86 or arm) that has an AES
accelerator, you really want to be using your accelerator than wasting
your cpu cycles on large blockes of AES...
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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