From: "Måns Rullgård" <mans@mansr.com>
To: linux-omap@vger.kernel.org
Subject: Re: OMAP3: Low DDR Memory bandwidth
Date: Wed, 04 Feb 2009 14:18:17 +0000 [thread overview]
Message-ID: <yw1xy6wms2ty.fsf@thrashbarg.mansr.com> (raw)
In-Reply-To: 703092.95158.qm@web112223.mail.gq1.yahoo.com
Ganeshan N <nganeshan1@yahoo.com> writes:
> Hi All,
> I am using OMAP3EVM and measuring DDR memory bandwidth. Used "lmbench"
> to measure the bandwidth. I am getting low bandwidth around 460 MB/S
> in TI kernel 2.6.22 and getting bandwidth around 800 MB/S in git
> kernel 2.6.28-rc8.
>
> In kernel 2.6.22, there are two SDRC registers (SDRC_DLLA_CTRL and
> SDRC_POWER_REG), which are getting modified. I have updated code such
> that SDRC values for both the the kernel 2.6.22 and 2.6.28 are
> same. After this updation there is no improvement in the bandwidth.
> The SDRC is running at 166MHz. I am using same x-loader and u-boot
> for both the kernel (2.6.22 and 2.6.28).
>
> Can you please suggest some pointers/methods, to increase the DDR
> memroy bandwidth in 2.6.22 TI kernel.
Check your cache settings. Enabling or disabling the L2 cache can
have dramatic effects on memory throughput. For mainly sequential
accesses disabling it can be faster.
--
Måns Rullgård
mans@mansr.com
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prev parent reply other threads:[~2009-02-04 14:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-04 12:47 OMAP3: Low DDR Memory bandwidth Ganeshan N
2009-02-04 13:14 ` Marek Vasut
2009-02-04 14:18 ` Måns Rullgård [this message]
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