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Date:      Thu, 21 Feb 2013 10:52:16 -0700
From:      Warner Losh <imp@bsdimp.com>
To:        Tim Kientzle <tim@kientzle.com>
Cc:        freebsd-arm@freebsd.org
Subject:   Re: MFCard access speed difference between RPi and Beaglebone
Message-ID:  <071CB345-EA30-4799-B59C-AFA6C1C03F83@bsdimp.com>
In-Reply-To: <337A8E96-9B28-4F98-8131-9E68A57B42E3@kientzle.com>
References:  <51263322.3030706@thieprojects.ch> <337A8E96-9B28-4F98-8131-9E68A57B42E3@kientzle.com>

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On Feb 21, 2013, at 10:02 AM, Tim Kientzle wrote:

> On Feb 21, 2013, at 6:45 AM, Werner Thie wrote:
>=20
>> Hi
>>=20
>> trying to nail down the crash and core dump in Python when importing =
ctypes I did a parallel build of python on both systems with the same =
SVN rev 246947 of kernel.
>>=20
>> The RPi seems to beat the Bbone quite clearly with a ration of 6 : 10
>>=20
>> It is very apparent (when unpacking for instance) that the Bb shows a =
much more pronounced 'hickup' behavior, unpacking 40-60 files and then =
most probably doing disk IO.
>>=20
>> Swapping the MFCards does not change the situation at all.
>>=20
>> Can anybody out there suppprt this observation and/or explain it?
>=20
> I've seen the same behavior with things like SVN checkouts;
> the BBone runs quite smoothly for a while and then stalls.
>=20
> I've been assuming that it was the MMCSD driver; skimming
> through the code, it looks like there's a lot of room for
> improvement.

I write mmcsd(4) for crappy hardware (the AT91RM9200's mmc controller =
was a new low in low performance), so I never got a chance to do much =
optimization.  I'm sure there's much low-hanging fruit there...

Warner




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