The code is simple. I'm using PRU Linux Application Loader API.
<http://processors.wiki.ti.com/index.php/PRU_Linux_Application_Loader_API_Guide>
void main (void)
{
//pru initialization...
u_int32_t ddrSizeInBytes = prussdrv_extmem_size();
u_int32_t *sharedDdr;
prussdrv_map_extmem(&sharedDdr);
u_int32_t* destination = new u_int32_t[76800]; //640*480*1 bytes
memcpy(sharedDdr, destination, sizeof(u_int32_t) * 76800); //takes
aprox 10-12 ms
u_int32_t* localSource = new u_int32_t[76800];
memcpy(localSource, destination, sizeof(u_int32_t) * 76800); //takes
aprox 0.5 - 1 ms
//close pru...
}
On Tuesday, April 18, 2017 at 8:09:44 PM UTC+3, William Hermans wrote:
> On Tue, Apr 18, 2017 at 4:38 AM, <[email protected] <javascript:>>
> wrote:
>
>> Hello,
>> I've encountered a problem with very slow reading speed from memory
>> allocated by pru kernel driver uio_pruss comparing to reading from usual
>> address spaces. Here is an performance tests on my Beagle Bone black:
>>
>> Average memcpy from pru DDR start address to application virtual address
>> (300 kB of data): 10.4781ms
>> Average cv::Mat.copyTo (300 kB of data): 11.0681ms
>> Average memcpy from one virtual address to another (300 kB of data):
>> 0.510001ms
>>
>> Kernel version is 4.4.12-bone11
>>
>> Can somebody explain the issue? May be I should have used new pru rpmesg
>> rproc driver?
>>
>
> I do not think anyone would be able to answer this question properly
> without at least doing a code review of your code. Also you're not really
> giving enough information as to what exactly it is that you're doing it. So
> to me, your numbers and times make sense, but your qualifiers do not mean
> anything to me.
>
> You also need to be aware that memcopy() is notoriously slow . . .
>
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