From 145c2d12f96d14c41896c91ef517404fbeaf350d Mon Sep 17 00:00:00 2001
From: Bimba Shrestha <bimbashrestha@fb.com>
Date: Thu, 11 Jun 2020 22:54:36 -0700
Subject: [PATCH] add hashtable head prefetching

---
 lib/compress/zstd_lazy.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/compress/zstd_lazy.c b/lib/compress/zstd_lazy.c
index 096980db3..fd76a55bb 100644
--- a/lib/compress/zstd_lazy.c
+++ b/lib/compress/zstd_lazy.c
@@ -525,6 +525,11 @@ size_t ZSTD_HcFindBestMatch_generic (
     /* HC4 match finder */
     U32 matchIndex = ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, mls);
 
+    if (dictMode == ZSTD_dictMatchState && ms->dictMatchState->enableDedicatedDictSearch)
+        PREFETCH_L1(ms->dictMatchState->hashTable +
+            (ZSTD_hashPtr(ip, ms->dictMatchState->cParams.hashLog - DD_BLOG,
+            ms->dictMatchState->cParams.minMatch) << DD_BLOG));
+
     for ( ; (matchIndex>lowLimit) & (nbAttempts>0) ; nbAttempts--) {
         size_t currentMl=0;
         if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
-- 
2.47.2