Amortize slice growth to avoid too many allocs

prashantv · Sep 10, 2023 · cd58493 · cd58493
1 parent 39666df
commit cd58493
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Showing 2 changed files with 20 additions and 17 deletions.
diff --git a/sorted_vs_heap/bench.out b/sorted_vs_heap/bench.out
@@ -2,21 +2,21 @@ goos: linux
 goarch: amd64
 pkg: github.com/prashantv/go-bench/sorted_vs_heap
 cpu: 13th Gen Intel(R) Core(TM) i5-13600KF
-BenchmarkSorted/1_shuffled_elems         	78202698	        16.18 ns/op	       8 B/op	       1 allocs/op
-BenchmarkSorted/1_sorted_elems           	74013729	        16.00 ns/op	       8 B/op	       1 allocs/op
-BenchmarkSorted/10_shuffled_elems        	 4999582	       241.4 ns/op	     160 B/op	       2 allocs/op
-BenchmarkSorted/10_sorted_elems          	 6413139	       187.6 ns/op	     160 B/op	       2 allocs/op
-BenchmarkSorted/100_shuffled_elems       	   57819	     20819 ns/op	    1536 B/op	       1 allocs/op
-BenchmarkSorted/100_sorted_elems         	  135454	      8888 ns/op	    1536 B/op	       1 allocs/op
-BenchmarkSorted/1000_shuffled_elems      	    1038	   1166869 ns/op	   17924 B/op	       3 allocs/op
-BenchmarkSorted/1000_sorted_elems        	    1886	    639461 ns/op	   17922 B/op	       3 allocs/op
-BenchmarkHeap/1_shuffled_elems           	97691158	        12.53 ns/op	       0 B/op	       0 allocs/op
-BenchmarkHeap/1_sorted_elems             	100000000	        12.23 ns/op	       0 B/op	       0 allocs/op
-BenchmarkHeap/10_shuffled_elems          	 6940164	       172.5 ns/op	       0 B/op	       0 allocs/op
-BenchmarkHeap/10_sorted_elems            	 7564102	       159.1 ns/op	       0 B/op	       0 allocs/op
-BenchmarkHeap/100_shuffled_elems         	  432127	      2798 ns/op	       0 B/op	       0 allocs/op
-BenchmarkHeap/100_sorted_elems           	  475987	      2528 ns/op	       0 B/op	       0 allocs/op
-BenchmarkHeap/1000_shuffled_elems        	   14500	     83782 ns/op	   11905 B/op	    1488 allocs/op
-BenchmarkHeap/1000_sorted_elems          	   16956	     70644 ns/op	   11905 B/op	    1488 allocs/op
+BenchmarkSorted/1_shuffled_elems         	138947696	         8.705 ns/op	       8 B/op	       0 allocs/op
+BenchmarkSorted/1_sorted_elems           	131542365	         9.205 ns/op	       8 B/op	       0 allocs/op
+BenchmarkSorted/10_shuffled_elems        	 5390264	       227.3 ns/op	      80 B/op	       1 allocs/op
+BenchmarkSorted/10_sorted_elems          	 7092080	       171.7 ns/op	      80 B/op	       1 allocs/op
+BenchmarkSorted/100_shuffled_elems       	   51919	     23113 ns/op	    1536 B/op	       1 allocs/op
+BenchmarkSorted/100_sorted_elems         	  117374	     10087 ns/op	    1536 B/op	       1 allocs/op
+BenchmarkSorted/1000_shuffled_elems      	     920	   1315147 ns/op	   17922 B/op	       3 allocs/op
+BenchmarkSorted/1000_sorted_elems        	    1621	    749301 ns/op	   17921 B/op	       3 allocs/op
+BenchmarkHeap/1_shuffled_elems           	93447892	        12.72 ns/op	       0 B/op	       0 allocs/op
+BenchmarkHeap/1_sorted_elems             	94744371	        12.66 ns/op	       0 B/op	       0 allocs/op
+BenchmarkHeap/10_shuffled_elems          	 6250802	       192.5 ns/op	       0 B/op	       0 allocs/op
+BenchmarkHeap/10_sorted_elems            	 6850843	       175.8 ns/op	       0 B/op	       0 allocs/op
+BenchmarkHeap/100_shuffled_elems         	  384812	      3156 ns/op	       0 B/op	       0 allocs/op
+BenchmarkHeap/100_sorted_elems           	  421676	      2860 ns/op	       0 B/op	       0 allocs/op
+BenchmarkHeap/1000_shuffled_elems        	   14072	     85918 ns/op	   11905 B/op	    1488 allocs/op
+BenchmarkHeap/1000_sorted_elems          	   16417	     73107 ns/op	   11905 B/op	    1488 allocs/op
 PASS
-ok  	github.com/prashantv/go-bench/sorted_vs_heap	22.279s
+ok  	github.com/prashantv/go-bench/sorted_vs_heap	24.100s
diff --git a/sorted_vs_heap/sorted_vs_heap_test.go b/sorted_vs_heap/sorted_vs_heap_test.go
@@ -18,6 +18,9 @@ func (ss sortedSlice) Less(i, j int) bool { return ss[i] < ss[j] }
 func (ss sortedSlice) Swap(i, j int)      { ss[i], ss[j] = ss[j], ss[i] }
 
 func (ss *sortedSlice) PushV(v int) {
+	if cap(*ss) == 0 {
+		*ss = make(sortedSlice, 0, 10)
+	}
 	*ss = append(*ss, v)
 	sort.Sort(ss)
 }