From 4cb6c3893638348ef261716ac47ede4f5f88b8e9 Mon Sep 17 00:00:00 2001 From: Ilya Tokar Date: Tue, 13 Dec 2022 13:57:36 -0800 Subject: Add prefetch to crc32 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We already prefetch in case of large inputs, do the same for medium sized inputs as well. This is mostly neutral for performance in most cases, so this also adds a new bench with working size >> cache size to ensure that we are seeing performance benefits of prefetch. Main benefits are on AMD with hardware prefetchers turned off: AMD prefetchers on: name old time/op new time/op delta BM_Calculate/0 2.43ns ± 1% 2.43ns ± 1% ~ (p=0.814 n=40+40) BM_Calculate/1 2.50ns ± 2% 2.50ns ± 2% ~ (p=0.745 n=39+39) BM_Calculate/100 9.17ns ± 1% 9.17ns ± 2% ~ (p=0.747 n=40+40) BM_Calculate/10000 474ns ± 1% 474ns ± 2% ~ (p=0.749 n=40+40) BM_Calculate/500000 22.8µs ± 1% 22.9µs ± 2% ~ (p=0.298 n=39+40) BM_Extend/0 1.38ns ± 1% 1.38ns ± 1% ~ (p=0.651 n=40+40) BM_Extend/1 1.53ns ± 2% 1.53ns ± 1% ~ (p=0.957 n=40+39) BM_Extend/100 9.48ns ± 1% 9.48ns ± 2% ~ (p=1.000 n=40+40) BM_Extend/10000 474ns ± 2% 474ns ± 1% ~ (p=0.928 n=40+40) BM_Extend/500000 22.8µs ± 1% 22.9µs ± 2% ~ (p=0.331 n=40+40) BM_Extend/100000000 4.79ms ± 1% 4.79ms ± 1% ~ (p=0.753 n=38+38) BM_ExtendCacheMiss/10 25.5ms ± 2% 25.5ms ± 2% ~ (p=0.988 n=38+40) BM_ExtendCacheMiss/100 23.1ms ± 2% 23.1ms ± 2% ~ (p=0.792 n=40+40) BM_ExtendCacheMiss/1000 37.2ms ± 1% 28.6ms ± 2% -23.00% (p=0.000 n=38+40) BM_ExtendCacheMiss/100000 7.77ms ± 2% 7.74ms ± 2% -0.45% (p=0.006 n=40+40) AMD prefetchers off: name old time/op new time/op delta BM_Calculate/0 2.43ns ± 2% 2.43ns ± 2% ~ (p=0.351 n=40+39) BM_Calculate/1 2.51ns ± 2% 2.51ns ± 1% ~ (p=0.535 n=40+40) BM_Calculate/100 9.18ns ± 2% 9.15ns ± 2% ~ (p=0.120 n=38+39) BM_Calculate/10000 475ns ± 2% 475ns ± 2% ~ (p=0.852 n=40+40) BM_Calculate/500000 22.9µs ± 2% 22.8µs ± 2% ~ (p=0.396 n=40+40) BM_Extend/0 1.38ns ± 2% 1.38ns ± 2% ~ (p=0.466 n=40+40) BM_Extend/1 1.53ns ± 2% 1.53ns ± 2% ~ (p=0.914 n=40+39) BM_Extend/100 9.49ns ± 2% 9.49ns ± 2% ~ (p=0.802 n=40+40) BM_Extend/10000 475ns ± 2% 474ns ± 1% ~ (p=0.589 n=40+40) BM_Extend/500000 22.8µs ± 2% 22.8µs ± 2% ~ (p=0.872 n=39+40) BM_Extend/100000000 10.0ms ± 3% 10.0ms ± 4% ~ (p=0.355 n=40+40) BM_ExtendCacheMiss/10 196ms ± 2% 196ms ± 2% ~ (p=0.698 n=40+40) BM_ExtendCacheMiss/100 129ms ± 1% 129ms ± 1% ~ (p=0.602 n=36+37) BM_ExtendCacheMiss/1000 88.6ms ± 1% 57.2ms ± 1% -35.49% (p=0.000 n=36+38) BM_ExtendCacheMiss/100000 14.9ms ± 1% 14.9ms ± 1% ~ (p=0.888 n=39+40) Intel skylake: BM_Calculate/0 2.49ns ± 2% 2.44ns ± 4% -2.15% (p=0.001 n=31+34) BM_Calculate/1 3.04ns ± 2% 2.98ns ± 9% -1.95% (p=0.003 n=31+35) BM_Calculate/100 8.64ns ± 3% 8.53ns ± 5% ~ (p=0.065 n=31+35) BM_Calculate/10000 290ns ± 3% 285ns ± 7% -1.80% (p=0.004 n=28+34) BM_Calculate/500000 11.8µs ± 2% 11.6µs ± 8% -1.59% (p=0.003 n=26+34) BM_Extend/0 1.56ns ± 1% 1.52ns ± 3% -2.44% (p=0.000 n=26+35) BM_Extend/1 1.88ns ± 3% 1.83ns ± 6% -2.17% (p=0.001 n=27+35) BM_Extend/100 9.31ns ± 3% 9.13ns ± 7% -1.92% (p=0.000 n=33+38) BM_Extend/10000 290ns ± 3% 283ns ± 3% -2.45% (p=0.000 n=32+38) BM_Extend/500000 11.8µs ± 2% 11.5µs ± 8% -1.80% (p=0.001 n=35+37) BM_Extend/100000000 6.39ms ±10% 6.11ms ± 8% -4.34% (p=0.000 n=40+40) BM_ExtendCacheMiss/10 36.2ms ± 7% 35.8ms ±14% ~ (p=0.281 n=33+37) BM_ExtendCacheMiss/100 26.9ms ±15% 25.9ms ±12% -3.93% (p=0.000 n=40+40) BM_ExtendCacheMiss/1000 23.8ms ± 5% 23.4ms ± 5% -1.68% (p=0.001 n=39+40) BM_ExtendCacheMiss/100000 10.1ms ± 5% 10.0ms ± 4% ~ (p=0.051 n=39+39) PiperOrigin-RevId: 495119444 Change-Id: I67bcf3b0282b5e1c43122de2837a24c16b8aded7 --- absl/crc/BUILD.bazel | 1 + 1 file changed, 1 insertion(+) (limited to 'absl/crc/BUILD.bazel') diff --git a/absl/crc/BUILD.bazel b/absl/crc/BUILD.bazel index 29374560..1c58f46c 100644 --- a/absl/crc/BUILD.bazel +++ b/absl/crc/BUILD.bazel @@ -204,6 +204,7 @@ cc_binary( deps = [ ":crc32c", "//absl/memory", + "//absl/strings", "@com_github_google_benchmark//:benchmark_main", ], ) -- cgit v1.2.3