"Efficient Go" Book Code Examples

Hi 👋

My name is Bartek Płotka and I wrote "Efficient Go". This book teaches pragmatic approaches to software efficiency and optimizations. While the majority of the learnings works for any programming language, it's best to learn on specific examples. For that purpose I teach how to make my favorite language more efficient - Go.

In this open-source repository you can find all examples from the book with tests, additional comments and more! Play with the examples to learn more about CPU, memory, OS and Go runtime characteristics I explained in my book!

NOTE: Don't import this module to your production code--it is meant for learning purposes only. Instead, we maintain production grade utilities mentioned in the book in core and e2e modules.

Index of Examples From Book

All examples from the book are buildable and tested in CI (as they should). See their location in the below table. For most of the code there exists corresponding _test.go file with tests and microbenchmarks when relevant.

For the book version before errata, see v1.0 branch.

NOTE: Some function names in examples might be different in book vs in code, due to name clashes. Code in the book might be also simplified. I also use non-conventional naming convention with some functions e.g. FailureRatio_Better. In Go all names should have camelCase form, so e.g. FailureRatioBetter. However, I chose to keep underscore to separate different versions of the same functions for book purposes - so the "production name" should is still FailureRatio! (:

Example Ref	Page	Path to code/function in this repository.
Example 1-1	9	pkg/getter/getter.go:13 FailureRatio
Example 1-2	10	pkg/getter/getter.go:29 FailureRatio_Better
Example 1-3	12	pkg/prealloc/slice.go:5 createSlice
Example 1-4	12	pkg/prealloc/slice.go:14 createSlice_Better
Example 1-5	13	pkg/notationhungarian/hung.go:5 structSystem
Example 2-1	37	pkg/basic/basic.go:6
Example 2-2	42	pkg/export/export.go:6
Example 2-3	44	Prometheus main.go
Example 2-4	48	pkg/errors/errors.go:8
Example 2-5	49	pkg/errors/errors.go:34
Example 2-6	51	pkg/basicserver/basicserver.go:10
Example 2-7	52	pkg/unused/unused.go:8
Example 2-8	53-54	pkg/testing/max_test.go:11
Example 2-9	55	pkg/godoc
Example 2-10	56	pkg/godoc
Example 2-11	59	pkg/oop/oop.go:14
Example 2-12	62	sort.Interface from the standard library
Example 2-13	62	pkg/oop/oop.go:58
Example 2-14	64	pkg/generics/sort.go:12
Example 2-15	65	pkg/generics/blocks.go:19
Example 3-3	93	pkg/jpeg/jpeg.go:12
Example 4-1	115	pkg/sum/sum.go:15 Sum
Example 4-5	139	pkg/concurrency/concurrency.go:12
Example 4-6	140	pkg/concurrency/concurrency.go:36
Example 4-7	140	pkg/concurrency/concurrency.go:55
Example 4-8	140	pkg/concurrency/concurrency.go:77
Example 5-1	162	pkg/memory/mmap/mmap.go:14
Example 5-2	164	pkg/memory/mmap/interactive/interactive_open.go:94
Example 5-3	165	pkg/memory/mmap/interactive/interactive_mmap.go:14
Example 5-4	179	pkg/memory/vars/vars.go:11
Example 5-5	183	pkg/memory/slice/slice.go:30
Example 5-6	187	pkg/memory/slice/slice.go:30
Example 6-1	199	pkg/metrics/latency_test.go:31
Example 6-2	200-201	pkg/metrics/latency_test.go:50
Example 6-3	201	pkg/metrics/latency_test.go:74
Example 6-4	203	pkg/metrics/latency_test.go:85
Example 6-6	206	pkg/metrics/latency_test.go:107
Example 6-7	211-212	pkg/metrics/latency_test.go:129
Example 6-9	214	pkg/metrics/prom.yaml
Example 6-11	231	pkg/metrics/cpu_test.go:19
Example 6-12	235	pkg/metrics/mem_test.go:69 printMemRuntimeMetric
Example 7-1	241	pkg/sum/sum.go:15 Sum
Example 8-1	279	pkg/sum/sum_test.go:49 BenchmarkSum
Example 8-2	281	pkg/sum/sum_test.go:49 BenchmarkSum
Example 8-9	291	pkg/sum/sum_test.go:76 TestSum
Example 8-10	292	pkg/sum/sum_test.go:49 BenchmarkSum
Example 8-11	293	pkg/sum/sum_test.go:116 TestBenchSum
Example 8-12	295	pkg/sum/sum_test.go:49 BenchmarkSum
Example 8-13	296	pkg/sum/sum_test.go:25 lazyCreateTestInput
Example 8-14	297	pkg/sum/sum_test.go:155 BenchmarkSum_AcrossInputs
Example 8-16	302	pkg/compileroptimizeaway/opt_away_test.go:11 BenchmarkPopcnt_Wrong
Example 8-18	304-305	pkg/compileroptimizeaway/opt_away_test.go:37 BenchmarkPopcnt_Sink
Example 8-19	312-313	pkg/sum/labeler/labeler_e2e_test.go:39 TestLabeler_LabelObject
Example 8-20	313-314	pkg/sum/labeler/labeler_e2e_test.go:39 TestLabeler_LabelObject
Example 9-1	333	pkg/profile/fd/fd.go
Example 9-2	334-336	pkg/profile/fd/example/main.go
Example 9-4	344	pkg/profile/fd/example/main.go:52
Example 9-5	358	pkg/profile/fd/http.go:12
Example 9-6	374-375	pkg/sum/labeler/labeler_e2e_test.go:39 TestLabeler_LabelObject
Example 10-2	385	pkg/sum/sum_test.go:142 BenchmarkSum_fgprof
Example 10-3	388	pkg/sum/sum.go:43 Sum2
Example 10-4	390-391	pkg/sum/sum.go:94 Sum3
Example 10-5	393	pkg/sum/sum.go:143 Sum4
Example 10-7	396	pkg/sum/sum.go:191 Sum5
Example 10-8	398-399	pkg/sum/sum.go:252 Sum6
Example 10-10	403	pkg/sum/sum_concurrent.go:18 ConcurrentSum1
Example 10-11	405-406	pkg/sum/sum_concurrent.go:49 ConcurrentSum2
Example 10-12	407-408	pkg/sum/sum_concurrent.go:109 ConcurrentSum3
Example 10-13	410	pkg/sum/sum_concurrent.go:181 ConcurrentSum4
Example 10-15	412	pkg/sum/sum.go:299 Sum7
Example 11-1	418	pkg/generics/dups.go:6
Example 11-2	428-429	pkg/leak/http_close.go:13
Example 11-3	429-430	pkg/leak/http_close_test.go:17 TestHandleCancel
Example 11-5	431-432	pkg/leak/http_close.go:39
Example 11-6	433	pkg/leak/http_close.go:87 Handle_Better
Example 11-7	434	pkg/leak/http_close_test.go:81
Example 11-8	435-436	pkg/leak/file.go:15
Example 11-9	437	pkg/leak/file.go:55
Example 11-10	438-439	pkg/leak/http_exhaust.go:13
Example 11-11	441	pkg/prealloc/prealloc_test.go:54
Example 11-12	442-443	pkg/prealloc/prealloc_test.go:99
Example 11-14	444-445	pkg/prealloc/linkedlist.go:6
Example 11-15	446	pkg/prealloc/linkedlist.go:39
Example 11-16	448	pkg/prealloc/linkedlist.go:57
Examples 11-17	450	pkg/pools/reuse.go:8
Examples 11-18	451-452	pkg/pools/reuse.go:8
Examples 11-19	452-453	pkg/pools/reuse.go:8
Examples 11-20	453	pkg/pools/reuse_test.go:39

Copyright Bartek Płotka