cmd/addchain: comprehensive profiling options (#98)

Implement comprehensive profiling options in the search subcommand, using the https://github.com/mmcloughlin/profile module. Profiles are configured with the ADDCHAIN_PROFILE environment variable. Removes the `-cpuprofile` option.

Updates #60
Updates #25

cmd/addchain/search.go

@@ -3,12 +3,10 @@ package main
 import (
 	"context"
 	"flag"
-	"os"
-	"os/signal"
 	"runtime"
-	"runtime/pprof"
 
 	"github.com/google/subcommands"
+	"github.com/mmcloughlin/profile"
 
 	"github.com/mmcloughlin/addchain/acc"
 	"github.com/mmcloughlin/addchain/acc/printer"
@@ -24,13 +22,12 @@ type search struct {
 
 	concurrency int
 	verbose     bool
-	cpuprofile  string
 }
 
 func (*search) Name() string     { return "search" }
 func (*search) Synopsis() string { return "search for an addition chain." }
 func (*search) Usage() string {
-	return `Usage: search [-v] [-p <N>] [-cpuprofile <file>] <expr>
+	return `Usage: search [-v] [-p <N>] <expr>
 
 Search for an addition chain for <expr>.
 
@@ -40,10 +37,16 @@ Search for an addition chain for <expr>.
 func (cmd *search) SetFlags(f *flag.FlagSet) {
 	f.IntVar(&cmd.concurrency, "p", runtime.NumCPU(), "run `N` algorithms in parallel")
 	f.BoolVar(&cmd.verbose, "v", false, "verbose output")
-	f.StringVar(&cmd.cpuprofile, "cpuprofile", "", "write cpu profile to `file`")
 }
 
 func (cmd *search) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) (status subcommands.ExitStatus) {
+	// Enable profiling.
+	defer profile.Start(
+		profile.AllProfiles,
+		profile.ConfigEnvVar("ADDCHAIN_PROFILE"),
+	).Stop()
+
+	// Parse arguments.
 	if f.NArg() < 1 {
 		return cmd.UsageError("missing expression")
 	}
@@ -60,32 +63,6 @@ func (cmd *search) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{})
 	cmd.Log.Printf("hex: %x", n)
 	cmd.Log.Printf("dec: %s", n)
 
-	// Start profiling.
-	if cmd.cpuprofile != "" {
-		f, err := os.Create(cmd.cpuprofile)
-		if err != nil {
-			return cmd.Fail("could not create cpu profile: %v", err)
-		}
-		defer cmd.CheckClose(&status, f)
-
-		if err := pprof.StartCPUProfile(f); err != nil {
-			return cmd.Fail("could not start cpu profile: %v", err)
-		}
-
-		go func() {
-			c := make(chan os.Signal, 1)
-			signal.Notify(c, os.Interrupt)
-			s := <-c
-
-			cmd.Log.Printf("caught %s: stopping cpu profile", s)
-			pprof.StopCPUProfile()
-
-			os.Exit(0)
-		}()
-
-		defer pprof.StopCPUProfile()
-	}
-
 	// Execute an ensemble of algorithms.
 	ex := exec.NewParallel()
 	if cmd.verbose {

go.mod

@@ -2,4 +2,7 @@ module github.com/mmcloughlin/addchain
 
 go 1.13
 
-require github.com/google/subcommands v1.2.0
+require (
+	github.com/google/subcommands v1.2.0
+	github.com/mmcloughlin/profile v0.1.1
+)

go.sum

@@ -1,2 +1,4 @@
 github.com/google/subcommands v1.2.0 h1:vWQspBTo2nEqTUFita5/KeEWlUL8kQObDFbub/EN9oE=
 github.com/google/subcommands v1.2.0/go.mod h1:ZjhPrFU+Olkh9WazFPsl27BQ4UPiG37m3yTrtFlrHVk=
+github.com/mmcloughlin/profile v0.1.1 h1:jhDmAqPyebOsVDOCICJoINoLb/AnLBaUw58nFzxWS2w=
+github.com/mmcloughlin/profile v0.1.1/go.mod h1:IhHD7q1ooxgwTgjxQYkACGA77oFTDdFVejUS1/tS/qU=