Hi David,
On Mon, Sep 25, 2017 at 09:30:28AM +0000, David Laight wrote:

From: wei.guo.simon@gmail.com

quoted

Sent: 21 September 2017 00:35
This patch adjust selftest memcmp_64 so that memcmp selftest can be
compiled successfully.

...

quoted

 #define ITERATIONS 10000

+#define LARGE_SIZE (5 * 1024)
+#define LARGE_ITERATIONS 1000

...

Measuring performance by doing a lot of iterations isn't ideal
and is pretty pointless.
Cold cache performance can be more useful.
Also you don't really want any dynamic branch prediction logic
tuned to the exact test you keep doing.

I think the (orignal) selftest aims at full coverage of functionality
correctness, since each iteration generates a new data set by random.

Thanks,
- Simon