Ira W. Snyder wrote:
> On Wed, Jul 08, 2009 at 05:58:50PM -0700, Ira W. Snyder wrote:
>> On Wed, Jul 08, 2009 at 07:32:26PM -0500, Peter Tyser wrote:
>>> On Thu, 2009-07-09 at 08:24 +0800, Liu Dave-R63238 wrote:
[snip]
>> Both the DMA and CPU methods are definitely on the same order of
>> magnitude. The time taken by the CFI flash driver is MUCH longer than
>> the SDRAM initialization. I wonder, should the icache be enabled for
>> that as well?
>>
>> I'll do some more testing when I get back to the office tomorrow.
>>
>
> Ok, I've added back the get_tbms() code, and created a routine to
> initialize ECC with the CPU. I've inlined my patch below, just for
> reference.
>
> DMA 945ms
> CPU 581ms
>
> As an interesting comparison, I also benchmarked the method of using the
> DDR controller to initialize ECC.
>
> DDRC 129ms
>
> So there you have it. Dave Liu is correct, the CPU method is faster,
> though definitely on the same order of magnitude with the
> icache_enable()/icache_disable() patch.
Thanks for the measurements and the update.
> I may stick with the DDRC method on my board, the difference is just
> amazing. The flash init still takes up most of the boot process,
> however.
>
> Peter, feel free to fold the patch below into your own work.
> Ira
[snip]
FWIIW, and it doesn't materially change your results, but it would have
been better to duplicate the get_tbms() call and put it directly around
the *_meminit() calls rather than having the print statements inside the
timed part. Since U-Boot printing is a blocking call (generally), you
are adding the UART Tx time to your measurement.
#if 0
debug("\nInitializing ECC (using DMA)!\n");
s = get_tbms();
dma_meminit(CONFIG_MEM_INIT_VALUE, dram_size);
#else
debug("\nInitializing ECC (using CPU)!\n");
s = get_tbms();
cpu_meminit(CONFIG_MEM_INIT_VALUE, dram_size);
#endif
e = get_tbms();
> + s = get_tbms();
> +#if 0
> + debug("\nInitializing ECC (using DMA)!\n");
> dma_meminit(CONFIG_MEM_INIT_VALUE, dram_size);
> +#else
> + debug("\nInitializing ECC (using CPU)!\n");
> + cpu_meminit(CONFIG_MEM_INIT_VALUE, dram_size);
> +#endif
> + e = get_tbms();
>
> debug("\nREADY!\n");
> + debug("ddr init duration: %ld ms\n", e - s);
>
> /* Clear All ECC Errors */
> if ((ddr->err_detect & ECC_ERROR_DETECT_MME) == ECC_ERROR_DETECT_MME)
Thanks,
gvb
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