commit c3c58fb560fcf1225d4bfb533ba41add8de910e4
author Christopher Ferris <cferris@google.com> Tue Oct 15 12:10:06 2013 -0700
committer Christopher Ferris <cferris@google.com> Tue Oct 15 12:10:06 2013 -0700
tree 71ebd92ad4bb233910c2019c0ab683d877241df3
parent abeafbd6d5e11044dd305e48134bc3d84319a3da

Modify prefetch for krait memcpy.

I originally modified the krait mainloop prefetch from cacheline * 8 to * 2.
This causes a perf degradation for copies bigger than will fit in the cache.
Fixing this back to the original * 8. I tried other multiples, but * 8 is th
sweet spot on krait.

Bug: 11221806

Change-Id: I1f75fad6440f7417e664795a6e7b5616f6a29c45

libc/arch-arm/krait/bionic/memcpy_base.S

diff --git a/libc/arch-arm/krait/bionic/memcpy_base.S b/libc/arch-arm/krait/bionic/memcpy_base.S
index cc1ab60..9984177 100644
--- a/libc/arch-arm/krait/bionic/memcpy_base.S
+++ b/libc/arch-arm/krait/bionic/memcpy_base.S
@@ -79,7 +79,7 @@
 1:      /* The main loop copies 64 bytes at a time */
         vld1.8      {d0  - d3},   [r1]!
         vld1.8      {d4  - d7},   [r1]!
-        pld         [r1, #(32*2)]
+        pld         [r1, #(32*8)]
         subs        r2, r2, #64
         vst1.8      {d0  - d3},   [r0, :128]!
         vst1.8      {d4  - d7},   [r0, :128]!