From: Yedidya Feldblum <yfeldblum@fb.com>
Date: Wed, 23 Sep 2015 05:22:20 +0000 (-0700)
Subject: Search unpadded strings in Range benchmarks
X-Git-Tag: deprecate-dynamic-initializer~381
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=606fa0b6dd06630eb3a26e1571a494a3df151711;p=folly.git

Search unpadded strings in Range benchmarks

Summary: [Folly] Search unpadded strings in `Range` benchmarks.

`vstr` has padding to adjust alignment. `vstrp` is a view into `vstr` that skips the padding, so that searches start out unaligned.

Before this diff, haystack is 8-byte aligned: `uintptr_t(haystack.begin()) % 8 == 0`. After this diff, it is not.

Reviewed By: @​@​nbronson

Differential Revision: D2468934
---

diff --git a/folly/test/RangeFindBenchmark.cpp b/folly/test/RangeFindBenchmark.cpp
index 2c920b72..2194ebb4 100644
--- a/folly/test/RangeFindBenchmark.cpp
+++ b/folly/test/RangeFindBenchmark.cpp
@@ -167,7 +167,7 @@ void countHits(Func func, size_t n) {
 template <class Func>
 void findFirstOfRange(StringPiece needles, Func func, size_t n) {
   FOR_EACH_RANGE (i, 0, n) {
-    const StringPiece haystack = vstr[i % kVstrSize];
+    const StringPiece haystack = vstrp[i % kVstrSize];
     doNotOptimizeAway(func(haystack, needles));
     char x = haystack[0];
     doNotOptimizeAway(&x);