praveen005 / word-counter

Running the Program

Build the Program:

go build -o main

Run the program:

./main

To print statistics about the resource usage of the command, including the elapsed real time, user CPU time, and system CPU time:

time ./main

Output would look like:

"ego.txt": 160578

real    0m2.102s
user    0m0.005s
sys     0m0.027s

real: Elapsed real (wall-clock) time. This is the actual time taken from the start to the end of the command's execution.

user: CPU time spent in user-mode code (outside the kernel). This includes the time spent executing your program's code.

sys: CPU time spent by the kernel on behalf of the command. This includes time spent on system calls and other kernel operations.

If you want to compare it with the inbuilf wc command:

time wc -w fileName.txt

Note: The time command is useful for profiling and understanding the performance characteristics of our programs.

Benchmarking

go test -bench=BenchmarkWC -benchmem

Baseline:

Benchmarking Result:

"ego.txt": 160578
goos: windows
goarch: amd64
pkg: wc
cpu: AMD Ryzen 5 5500U with Radeon Graphics
BenchmarkWC-12                 1        2029952200 ns/op         1018296 B/op    1015315 allocs/op
PASS
ok      wc      2.368s

Time Stats:

"ego.txt": 160578

real    0m2.406s
user    0m0.003s
sys     0m0.076s

Resource Stats for standard wc command:

Note: There's a difference between word count here, that is because, there are some forms of words that I'm not considering.

161916 ego.txt

real    0m0.117s
user    0m0.020s
sys     0m0.076s

Profiling:

CPU Profile:

go test -cpuprofile cpu.prof -bench .

Visualize the profile in web:

go tool pprof -http=:8080 cpu.prof

Want a PNG image of the profile?

Enter the interactive pprof shell:

go tool pprof cpu.prof

Now type png in there and press Enter

Want more control?

Specify the output file name and create image of a particular binary:

go tool pprof -output="profile.png" wc.test.exe cpu.prof

This will again open pprof interactive shell. Type in png there and press Enter

Note: Enter your own binary file name in place of wc.test.exe

Optimization

1. Buffered Reading: Instead of reading Byte by Byte, we'll read the data in chunks and store in internal buffer, thereby reducing the number of direct interactions with the file.

This improves the performance significantly:

Benchmark:

goos: windows
goarch: amd64
pkg: wc
cpu: AMD Ryzen 5 5500U with Radeon Graphics
BenchmarkWC-12                52          24686375 ns/op         1020061 B/op    1015300 allocs/op
PASS
ok      wc      1.660s

Time Stats for our program:

"ego.txt": 160578

real    0m0.153s
user    0m0.003s
sys     0m0.026s

Time Stats for inbuilt wc command(for comparison):

161916 ego.txt

real    0m0.119s
user    0m0.013s
sys     0m0.066s

More

The above way of create profile is based on using the command line flags. Use it when you need the profile of the complete program.

If you want to create profile for a particular block of code do the following:

cpuProfileFile, err := os.Create("cpu_profile.prof")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error creating CPU profile file: %v\n", err)
		os.Exit(1)
	}
	defer cpuProfileFile.Close()
	pprof.StartCPUProfile(cpuProfileFile)
	----- your code here------
	pprof.StopCPUProfile()

To create the profile, simply run:

go run main.go

It will create a cpu_profile.prof file.

To analyze:

go tool pprof cpu_profile.prof

Then type in web inside the pprof shell and press Enter Aliter:

go tool pprof -http=:8080 cpu_profile.prof