profiling

Profiling

Different ways to profile:

• Debug Endpoint
• Uplink Profiling

Debug Endpoint

The Satellite and storage nodes run an http service with debug endpoints. By default it uses a random port when the service is started so look in the storj-sim logs to find the debug port.

The debug endpoints can be used to look at the cpu or heap profile or to create an execution trace. See these go docs for details.

For example, create a 30 second cpu profile of the satellite running locally with this command:

curl "localhost:<saDebugPort>/debug/pprof/profile?seconds=30" -o cpu.prof

Create a memory profile of the satellite running locally with this command:

curl "localhost:<saDebugPort>/debug/pprof/heap" -o mem.prof

Unlike the CPU profile, this command creates a "snapshot" of the memory profile at a given time, rather than over an interval like 30 seconds. For example, one may need to curl the memory profile several times over the course of a load test as stress on the Satellite grows.

Reference:

• debug endpoint source code
• go pprof docs

Uplink profiling

To create a cpu or memory profile for the uplink, use the following flags --profile.cpu and --profile.mem.

For example, to create a cpu profile of a download, run:

// generate profile
$ uplink --profile.cpu=cpu.prof cp sj://testbucket/file.test .

// view profile
$ go tool pprof -http :6060 cpu.prof

To create a memory profile of a download, run:

$ uplink --profile.mem=mem.prof cp sj://testbucket/file.test .