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Reduce cache misses for source_gemm_r
- From: Max Bruce <max dot bruce12 at gmail dot com>
- To: gsl-discuss at sourceware dot org
- Date: Thu, 18 Oct 2018 20:10:42 -0700
- Subject: Reduce cache misses for source_gemm_r
Hey guys,
I'm new to contributing to GNU projects, but... I'm guessing I send
commits through here? Would appreciate some sort of note on the
procedure on the website
I noticed that your matrix multiplication code had bad cache
performance due to a misordering of a loop. In a replicated version of
my change, I saw about 20% performance gains on my AMD FX CPU.
Do let me know if this is not the correct contribution procedure.
-Max
From 0345eaf2eb48997fa3d00fae2b37cf416d3713d4 Mon Sep 17 00:00:00 2001
From: JavaProphet <max.bruce12@gmail.com>
Date: Thu, 18 Oct 2018 20:00:47 -0700
Subject: [PATCH] Reduce cache misses for source_gemm_r
---
cblas/source_gemm_r.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/cblas/source_gemm_r.h b/cblas/source_gemm_r.h
index a008d22..7c9848e 100644
--- a/cblas/source_gemm_r.h
+++ b/cblas/source_gemm_r.h
@@ -71,8 +71,8 @@
/* form C := alpha*A*B + C */
- for (k = 0; k < K; k++) {
- for (i = 0; i < n1; i++) {
+ for (i = 0; i < n1; i++) {
+ for (k = 0; k < K; k++) {
const BASE temp = alpha * F[ldf * i + k];
if (temp != 0.0) {
for (j = 0; j < n2; j++) {
@@ -86,8 +86,8 @@
/* form C := alpha*A*B' + C */
+ for (j = 0; j < n2; j++) {
for (i = 0; i < n1; i++) {
- for (j = 0; j < n2; j++) {
BASE temp = 0.0;
for (k = 0; k < K; k++) {
temp += F[ldf * i + k] * G[ldg * j + k];
@@ -98,8 +98,8 @@
} else if (TransF == CblasTrans && TransG == CblasNoTrans) {
+ for (i = 0; i < n1; i++) {
for (k = 0; k < K; k++) {
- for (i = 0; i < n1; i++) {
const BASE temp = alpha * F[ldf * k + i];
if (temp != 0.0) {
for (j = 0; j < n2; j++) {
@@ -111,8 +111,8 @@
} else if (TransF == CblasTrans && TransG == CblasTrans) {
+ for (j = 0; j < n2; j++) {
for (i = 0; i < n1; i++) {
- for (j = 0; j < n2; j++) {
BASE temp = 0.0;
for (k = 0; k < K; k++) {
temp += F[ldf * k + i] * G[ldg * j + k];
--
2.7.4