---
title: "Profiling"
date: 2021-08-24T12:32:20+01:00
weight: 56
geekdocRepo: https://github.com/owncloud/ocis
geekdocEditPath: edit/master/docs/ocis/development
geekdocFilePath: profiling.md
---

{{< toc >}}

The only way to enable the profiler currently is to explicitly select which areas to collect samples for. In order to do this, the following steps have to be followed.

## 1. Clone Reva

`git clone github.com/cs3org/reva`

## 2. Patch reva with the area that you want sampled.

For the purposes of this docs let's use the WebDAV `PROPFIND` path.

```diff
diff --git a/internal/http/services/owncloud/ocdav/propfind.go b/internal/http/services/owncloud/ocdav/propfind.go
index 0e9c99be..f271572f 100644
--- a/internal/http/services/owncloud/ocdav/propfind.go
+++ b/internal/http/services/owncloud/ocdav/propfind.go
@@ -32,6 +32,8 @@ import (
        "strings"
        "time"

+       _ "net/http/pprof"
+
        userv1beta1 "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
        rpc "github.com/cs3org/go-cs3apis/cs3/rpc/v1beta1"
        link "github.com/cs3org/go-cs3apis/cs3/sharing/link/v1beta1"
@@ -311,6 +313,12 @@ func requiresExplicitFetching(n *xml.Name) bool {
        return true
 }

+func init() {
+       go func() {
+               http.ListenAndServe(":1234", nil)
+       }()
+}
+
 // from https://github.com/golang/net/blob/e514e69ffb8bc3c76a71ae40de0118d794855992/webdav/xml.go#L178-L205
 func readPropfind(r io.Reader) (pf propfindXML, status int, err error) {
        c := countingReader{r: r}
```

The previous patch will:

1. import `net/http/pprof`, which will register debug handlers in `DefaultServeMux`.
2. define a `init()` function that starts an http server with the previously registered handlers.

With everything running one should have access to http://localhost:1234/debug/pprof/

## 3. Replace ocis go.mod to local reva and build a new binary

```diff
diff --git a/go.mod b/go.mod
index 131d14d7b..9668c38e4 100644
--- a/go.mod
+++ b/go.mod
@@ -78,6 +78,7 @@ require (

 replace (
        github.com/crewjam/saml => github.com/crewjam/saml v0.4.5
+       github.com/cs3org/reva => path/to/your/reva
        go.etcd.io/etcd/api/v3 => go.etcd.io/etcd/api/v3 v3.0.0-20210204162551-dae29bb719dd
        go.etcd.io/etcd/pkg/v3 => go.etcd.io/etcd/pkg/v3 v3.0.0-20210204162551-dae29bb719dd
 )
```

Make sure to replace `github.com/cs3org/reva => path/to/your/reva` with the correct location of your reva.

## 4. Build a new ocis binary

From owncloud/ocis root:

```console
$ cd ocis
$ make clean build
```

## 5. Start oCIS server

From owncloud/ocis root:

```console
$ OCIS_LOG_PRETTY=true OCIS_LOG_COLOR=true ocis/bin/ocis server
```

## 6. Run `pprof`

### Install pprof

If `pprof` is not installed make sure to get it; one way of installing it is using the Go tools:

```console
$ go get -u github.com/google/pprof
```

### Collecting samples

Collect 30 seconds of samples:

```console
$ prof -web http://:1234/debug/pprof/profile\?seconds\=30
```

Once the collection is done a browser tab will open with the result `svg`, looking similar to this:

![img](https://i.imgur.com/vo0EbcX.jpg)

For references on how to interpret this graph, [continue reading here](https://github.com/google/pprof/blob/master/doc/README.md#interpreting-the-callgraph).

## References

- https://medium.com/swlh/go-profile-your-code-like-a-master-1505be38fdba
- https://dave.cheney.net/