On 2013-10-23 13:05, Tom Stellard wrote:
> + si_pm4_set_reg(pm4, R_00B82C_COMPUTE_MAX_WAVE_ID,
> + 0x190 /* Default value */);
Is there any visible effect on performance if this is set very low?
I haven't tested with any other values.
OK, I'll give it a test later and send a patch to compute the value if
it affects performance. I'm not certain what it's used for. (Maybe
related to COMPUTE_TMPRING_SIZE scratch allocation?)
If there is, perhaps we should compute this value for SI. I think all
the necessary parameters are provided by DRM (MAX_SE * MAX_SH_PER_SE *
MAX_PIPES * 40 wavefronts per CU, off the top of my head).
The formula from the comment is:
(number of compute units) * 4 * (waves per simd) - 1
I think this may be a simplified version of your formula.
Yes, although I omitted the - 1 by mistake. That's why it the value
struck me as odd, because 0x190 is unlikely to be the last wavefront ID.
0x18F perhaps, but I calculate 0x31F for Pitcairn, which is
significantly higher.
Anyhow, it doesn't this patch. Your patch looks good to me.
--
Jay Cornwall
http://www.jcornwall.me/
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