dtraceStacksToPprof

DTraceStacksToPprof

This is a tool used to convert performance profiles collected from DTrace to pprof, enabling graphical representation of the frequency of occuring stacks.

Getting started

First clone the repo,

$ git clone https://github.com/google/dtraceStacksToPprof.git

The tool requires Go, which can be downloaded at the Go homepage

dtraceStacksToPprof can be installed to the GOPATH using

go install github.com/google/dtraceStacksToPprof

or run directly in the repo using

go run main.go

How to use

The converter supports stack output produced by DTrace, in the following pseudo BNF syntax:

  <input> ::= <prologue> <stacks>
  <prologue> = { JUNK_LINE }
  <stacks> ::= { <stack> }
  <stack> ::= STACK_HEADER <frames> COUNT
  <frames> ::= { <frame> }
  <frame> ::= HEX_ADDRESS | FUNCTION
  JUNK_LINE ::= (string not matching STACK_HEADER)
  STACK_HEADER ::= ^\s*[\S\s]+\s*:$  (a sentence ending with a colon, optionally
                                      surrounded by white space)
  COUNT ::= ^\s*[0-9]+\s*$  (a sole decimal digit, optionally surrounded by
                             white space)
  HEX_ADDRESS ::= ^\s*0x[0-9a-fA-F]+\s*$ (a hexadecimal address, optionally
                                          surrounded by white space)
  FUNCTION ::= ^\s*[\S]+`.*\+?\S*$ (non-whitespace, backtick, non-whitespace,
                                    followed by an optional plus sign and
                                    optional non-whitespace after, all
                                    optionally surrounded by white space)

It's designed to take the output of dtrace scripts like the following:

#!/bin/dtrace -s
syscall:::entry {
  @aggr["Label:", ustack()] = count();
}
tick-1s {
  printa(@aggr);
}

The dtraceStacksToPprof tool reads text from stdin and produces a pprof protobuf. To produce a pprof directly from dtrace, simply pipe dtrace's output into dtraceStacksToPprof like

$ sudo dtrace -s <script name> -p <target pid> | dtraceStacksToPprof

or store to an intermediate text file and then convert.

$ dtraceStacksToPprof < <intermediate file>

The tool writes to profile.pb.gz by default, but the output file name can be customized via the --output command line flag:

$ dtraceStacksToPprof --output InterestingBehavior.pb.gz < <intermediate file>

Disclaimer

This is not an officially supported Google product.