From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: optimize memcpy_{from,to}io() and memset_io()
Date: Fri, 1 Aug 2014 09:32:46 +0100 [thread overview]
Message-ID: <20140801083245.GE15733@arm.com> (raw)
In-Reply-To: <20140801063009.GA24602@codeaurora.org>
On Fri, Aug 01, 2014 at 07:30:09AM +0100, Joonwoo Park wrote:
> + Catalin, Will
>
> Thanks,
> Joonwoo
> On Tue, Jul 29, 2014 at 11:28:26PM -0700, Joonwoo Park wrote:
> > Optimize memcpy_{from,to}io() and memset_io() by transferring in 64 bit
> > as much as possible with minimized barrier usage. This simplest optimization
> > brings faster throughput compare to current byte-by-byte read and write with
> > barrier in the loop. Code's skeleton is taken from the powerpc.
Hmm, I've never really understood the use-case for memcpy_{to,from}io on
ARM, so getting to the bottom of that would help in reviewing this patch.
Can you point me at the drivers which are using this for ARM please? Doing a
blind byte-by-byte copy could easily cause problems with some peripherals,
so there must be an underlying assumption somewhere about how this is
supposed to work.
Will
next prev parent reply other threads:[~2014-08-01 8:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-30 6:28 [PATCH] arm64: optimize memcpy_{from,to}io() and memset_io() Joonwoo Park
2014-08-01 6:30 ` Joonwoo Park
2014-08-01 8:32 ` Will Deacon [this message]
2014-08-02 1:38 ` Joonwoo Park
2014-08-04 9:57 ` Will Deacon
2014-10-03 16:31 ` Catalin Marinas
2014-10-09 2:39 ` Joonwoo Park
2014-10-09 10:16 ` Catalin Marinas
2014-10-14 4:04 ` Joonwoo Park
2014-10-14 4:12 ` Joonwoo Park
2014-10-20 13:33 ` Catalin Marinas
-- strict thread matches above, loose matches on Subject: below --
2014-10-21 0:59 Joonwoo Park
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