On 02/25/2016 06:03 PM, Sheng Yang wrote:
-#define DATA_SIZE (257 * 4096)
+#define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)
So the reason this was 25*7* was because in testing I saw repeated lengths
of size 512KiB, and due to the ring not being able to be completely used (a
limitation of the circular buffer logic) this would result in only one
request and the second having to wait. Another page allowed 2 to fit at once
:) so now that we're not using a ring any more this can probably just be 256
and still fit 2 512KiB allocations.
Sure. Would update.
In fact I just run another test again 256 * 4096, and found there are
many requests just 1MB long. So the following warning is triggered:
"TCMU: Request of size 4160/1048576 may be too big for 65408/1048576
cmd/data ring buffers."
Probably we want to increase the buffer size a bit?
But also it shows that we cannot accommodate all the upper layer
request in the buffer... There is no way we can allocate 1MB buffer
for each request.
I thought we could allocate an exactly 1MB buffer, with your changes,
no? That warning message may need to be changed.
-- Andy
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