Changes between Initial Version and Version 1 of LibCSSE

Timestamp:

May 6, 2014, 5:20:45 PM (12 years ago)

Author:

john

Comment:

--

LibCSSE

@@ +1 @@
+The first routine I worked on was memcpy().
+
+Comparison of stock memcpy() of a single page on FreeBSD vs Linux on a Westmere (values are TSC deltas):
+
+{{{
+x fbsd/westmere/builtin
++ linux/builtin
+    N           Min           Max        Median           Avg        Stddev
+x 1000           336         18444           340       361.628     573.11483
++ 1000           276          9996           280       288.924     307.34136
+Difference at 95.0% confidence
+        -72.704 +/- 40.3074
+        -20.1046% +/- 11.1461%
+        (Student's t, pooled s = 459.847)
+}}}
+
+||= Idea                       =||= Westmere      =||= Sandy Bridge  =||= Ivy Bridge    =||
+|| Replace `dec` with `sub`     || none            || none            || none            ||
+|| Use movsd instead of movsq   || slightly slower || slightly slower || 6% faster       ||
+|| Simple `movdqa` loop         || 138% slower     || 58% slower      || 46% slower      ||
+|| `movdqa` 32 at a time (old)  || 27% slower      || 14% faster      || 17% faster      ||
+|| `movdqa` 32 at a time (new)  || 27% slower      || 15% faster      || 18% faster      ||
+|| `movdqa` 64 at a time        || 224% slower     || 131% slower     || 116% slower     ||