debug-guide.md added memory statistics command

License: MIT
Signed-off-by: Rob Deutsch <rdeutschob@gmail.com>

docs/debug-guide.md

@@ -5,7 +5,8 @@ This is a document for helping debug go-ipfs. Please add to it if you can!
 ### Table of Contents
 - [Beginning](#beginning)
 - [Analysing the stack dump](#analysing-the-stack-dump)
-- [Analyzing the CPU Profile](#analyzing-the-cpu-profile)
+- [Analysing the CPU Profile](#analysing-the-cpu-profile)
+- [Analysing vars and memory statistics](#analysing-vars-and-memory-statistics)
 - [Other](#other)
 
 ### Beginning
@@ -20,6 +21,8 @@ profiling information.
   - `curl localhost:5001/debug/pprof/profile > ipfs.cpuprof`
 - heap trace dump
   - `curl localhost:5001/debug/pprof/heap > ipfs.heap`
+- memory statistics (in json, see "memstats" object)
+  - `curl localhost:5001/debug/vars > ipfs.vars`
 - system information
   - `ipfs diag sys > ipfs.sysinfo`
 
@@ -75,18 +78,22 @@ that goroutine in the middle of a short wait for something. If the wait time is
 over a few minutes, that either means that goroutine doesn't do much, or
 something is pretty wrong.
 
-### Analyzing the CPU Profile
+### Analysing the CPU Profile
 
 The go team wrote an [excellent article on profiling go
 programs](http://blog.golang.org/profiling-go-programs). If you've already
 gathered the above information, you can skip down to where they start talking
-about `go tool pprof`. My go-to method of analyzing these is to run the `web`
+about `go tool pprof`. My go-to method of analysing these is to run the `web`
 command, which generates an SVG dotgraph and opens it in your browser. This is
 the quickest way to easily point out where the hot spots in the code are.
 
+### Analysing vars and memory statistics
+
+The output is JSON formatted and includes badger store statistics, the command line run, and the output from Go's [runtime.ReadMemStats](https://golang.org/pkg/runtime/#ReadMemStats). The [MemStats](https://golang.org/pkg/runtime/#MemStats) has useful information about memory allocation and garbage collection.
+
 ### Other
 
-If you have any questions, or want us to analyze some weird go-ipfs behaviour,
+If you have any questions, or want us to analyse some weird go-ipfs behaviour,
 just let us know, and be sure to include all the profiling information
 mentioned at the top.