Re: [RFC PATCH v5] IV Generation algorithms for dm-crypt

From: Binoy Jayan <binoy.jayan@linaro.org>
To: Milan Broz <gmazyland@gmail.com>
Cc: Oded <oded.golombek@arm.com>, Ofir <Ofir.Drang@arm.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	linux-crypto@vger.kernel.org, Mark Brown <broonie@kernel.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Linux kernel mailing list <linux-kernel@vger.kernel.org>,
	Alasdair Kergon <agk@redhat.com>,
	Mike Snitzer <snitzer@redhat.com>,
	dm-devel@redhat.com, Shaohua Li <shli@kernel.org>,
	linux-raid@vger.kernel.org, Rajendra <rnayak@codeaurora.org>,
	Gilad <gilad@benyossef.com>
Subject: Re: [RFC PATCH v5] IV Generation algorithms for dm-crypt
Date: Thu, 13 Apr 2017 14:16:43 +0530	[thread overview]
Message-ID: <CAHv-k_98gM8Je+Yi5+Yj5s=6-qxNuuYY1x=ypy_dk6gL=WqyKg@mail.gmail.com> (raw)
In-Reply-To: <774a9713-05ef-0162-0203-461254a04f6e@gmail.com>

Hi Milan,

On 10 April 2017 at 19:30, Milan Broz <gmazyland@gmail.com> wrote:

Thank you for the reply.

> Well, it is good that there is no performance degradation but it
> would be nice to have some user of it that proves it is really
> working for your hw.

I have been able to get access to a hardware with IV generation support
a few days back. The hardware I was having before did not have IV
generation support. Will be able to come up with numbers after making
it work with the new one.

> FYI - with patch that increases dmcrypt sector size to 4k
> I can see improvement in speed usually in 5-15% with sync AES-NI
> (depends on access pattern), with dmcrypt mapped to memory
> it is even close to 20% speed up (but such a configuration is
> completely artificial).
>
> I wonder why increased dmcrypt sector size does not work for your hw,
> it should help as well (and can be combiuned later with this IV approach).
> (For native 4k drives this should be used in future anyway...)

I think it should work well too with backward incompatibility.

Thanks,
Binoy