From: "Mark Chambers" <markc@mail.com>
To: "Absolut Hunter" <absoluthunter@comcast.net>,
<linuxppc-embedded@ozlabs.org>
Subject: Re: Linux 2.4.25 / MPC8280 / ram config vs Linux instability?
Date: Mon, 11 Jul 2005 10:03:35 -0400 [thread overview]
Message-ID: <007d01c58621$55b8e2f0$0301a8c0@chuck2> (raw)
In-Reply-To: 20050711134713.D767067C13@ozlabs.org
> I am using U-boot to configure up the SDRAM and SRAM in our system before
we
> launch Linux. We have 32 Mb of SDRAM and 2 MB of SRAM in the system.
>
> If I leave the SRAM mapped at higher addresses 0x10000000 and SDRAM at
> 0x00000000, like U-boot defaults to Linux works great. However, my goal is
> to map SRAM <8ns speeds> down to the address 0x00000000, to map the vector
> table, so I can achieve a very fast interrupt response time.
>
Your core is probably running at about 400MHz, so 66MHz SRAM is still slow.
This is what cache is for. Maybe you should look into locking interrupt
code in
cache. Probably, however, you will find that messing with the overall
optimizations
of the kernel will be a net slowdown.
Mark Chambers
next prev parent reply other threads:[~2005-07-11 14:02 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-11 13:38 Linux 2.4.25 / MPC8280 / ram config vs Linux instability? Absolut Hunter
2005-07-11 14:01 ` Michael Richardson
2005-07-11 14:03 ` Mark Chambers [this message]
2005-07-11 14:22 ` Wolfgang Denk
2005-11-02 13:49 ` About 2.6.14 on AMCC Yosemite board KylongMu
2005-11-02 16:46 ` Wolfgang Denk
2005-11-06 15:55 ` Today's 2.6.14 can't finish build with yosemite-defconfig KylongMu
2005-11-11 2:04 ` 11-11-05 2.6.14 on AMCC Yosemite board(boot error) KylongMu
2005-11-11 8:39 ` Wolfgang Denk
2005-11-12 16:47 ` KylongMu
2005-11-12 18:01 ` Problem solved: " KylongMu
2005-11-12 23:32 ` Wolfgang Denk
2005-11-12 23:30 ` Wolfgang Denk
2005-07-11 18:39 ` Linux 2.4.25 / MPC8280 / ram config vs Linux instability? Dan Malek
-- strict thread matches above, loose matches on Subject: below --
2005-07-11 13:59 Steven Blakeslee
2005-07-11 14:02 Absolut Hunter
2005-07-11 14:39 ` Michael Richardson
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