Initial Look at OpenCL Accelerated SQLite Performance numbers on Mali

Hi Pete,

Thanks again for your suggestions. I'm still working on the code a bit yet but it's looking good. Performing:

SELECT id, uniformi, normali5 FROM test WHERE uniformi > 60 AND normali5 < 0

sqlite built -O2

CPU sql1 took 43631 microseconds

OpenCL sql1  took 14545 microseconds  (2.99x or 199% better) 

OpenCL (using vectors) 4114 microseconds (10.6x better or 960%)

The improvement not only resulted from working with vectors over arrays of integers but by also reducing the number of registers in use. I was able to jump from 64 to 128 work units.

The heart of the OpenCL kernel evolved from:

    do {

        if ((data[offset].v > 60) && (data[offset].w < 0)) {

            resultArray[roffset].id = data[offset].id;

            resultArray[roffset].v = data[offset].v;

            resultArray[roffset].w = data[offset].w;

            roffset++;

        }  

        offset++;

        endRow--;

    } while (endRow);

to

    do {

        v1 = vload4(0, data1+offset);

        v2 = vload4(0, data2+offset);

        r = (v1 > 60) && ( 0 > v2);

        vstore4(r,0, resultMask+offset);

        offset+=4;

        totalRows--;

    } while (totalRows);

Thanks again. If i can knock down one little bug I anticipate I'll be posting my code tomorrow. I've a curious situation where 2 results (out of 100,000 rows) aren't being matched and I'm not sure why. What I wouldn't give for an OpenCL debugger!

Hi Pete,

Thanks again for your suggestions. I'm still working on the code a bit yet but it's looking good. Performing:

SELECT id, uniformi, normali5 FROM test WHERE uniformi > 60 AND normali5 < 0

sqlite built -O2

CPU sql1 took 43631 microseconds

OpenCL sql1  took 14545 microseconds  (2.99x or 199% better) 

OpenCL (using vectors) 4114 microseconds (10.6x better or 960%)

The improvement not only resulted from working with vectors over arrays of integers but by also reducing the number of registers in use. I was able to jump from 64 to 128 work units.

The heart of the OpenCL kernel evolved from:

    do {

        if ((data[offset].v > 60) && (data[offset].w < 0)) {

            resultArray[roffset].id = data[offset].id;

            resultArray[roffset].v = data[offset].v;

            resultArray[roffset].w = data[offset].w;

            roffset++;

        }  

        offset++;

        endRow--;

    } while (endRow);

to

    do {

        v1 = vload4(0, data1+offset);

        v2 = vload4(0, data2+offset);

        r = (v1 > 60) && ( 0 > v2);

        vstore4(r,0, resultMask+offset);

        offset+=4;

        totalRows--;

    } while (totalRows);

Thanks again. If i can knock down one little bug I anticipate I'll be posting my code tomorrow. I've a curious situation where 2 results (out of 100,000 rows) aren't being matched and I'm not sure why. What I wouldn't give for an OpenCL debugger!

Hi Tom,

Thanks again for your suggestions.

No problem - happy to help. Writing optimal GPGPU code generally requires spotting where you can orientate your world 90 degrees and run on the walls - it takes a bit of getting used to.

OpenCL (using vectors) 4114 microseconds (10.6x better or 960%)

Sweet =)

Cheers,
P