Re: [Qemu-devel] [RFC PATCH v2 7/8] tracetool: Add support for the 'dtrace' backend

[Alon Levy <alevy@redhat.com>]

On Mon, Mar 26, 2012 at 07:38:23PM +0200, Lluís Vilanova wrote:
> Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
> ---
>  scripts/tracetool.py                |   31 ++++++++++
>  scripts/tracetool/__init__.py       |    8 +++
>  scripts/tracetool/backend/dtrace.py |  104 +++++++++++++++++++++++++++++++++++
>  scripts/tracetool/format/d.py       |   20 +++++++
>  scripts/tracetool/format/stap.py    |   20 +++++++
>  5 files changed, 183 insertions(+), 0 deletions(-)
>  create mode 100644 scripts/tracetool/backend/dtrace.py
>  create mode 100644 scripts/tracetool/format/d.py
>  create mode 100644 scripts/tracetool/format/stap.py
> 
> diff --git a/scripts/tracetool.py b/scripts/tracetool.py
> index 22623ae..2dd9da0 100755
> --- a/scripts/tracetool.py
> +++ b/scripts/tracetool.py
> @@ -44,6 +44,11 @@ Options:
>      --help                   This help message.
>      --list-backends          Print list of available backends.
>      --check-backend          Check if the given backend is valid.
> +    --binary <path>          Full path to QEMU binary.
> +    --target-type <type>     QEMU emulator target type ('system' or 'user').
> +    --target-arch <arch>     QEMU emulator target arch.
> +    --probe-prefix <prefix>  Prefix for dtrace probe names
> +                             (default: qemu-<target-type>-<target-arch>).\
>  """ % {
>              "script" : _SCRIPT,
>              "backends" : backend_descr,
> @@ -71,6 +76,10 @@ def main(args):
>      check_backend = False
>      arg_backend = ""
>      arg_format = ""
> +    binary = None
> +    target_type = None
> +    target_arch = None
> +    probe_prefix = None
>      for opt, arg in opts:
>          if opt == "--help":
>              error_opt()
> @@ -87,6 +96,15 @@ def main(args):
>          elif opt == "--check-backend":
>              check_backend = True
>  
> +        elif opt == "--binary":
> +            binary = arg
> +        elif opt == '--target-type':
> +            target_type = arg
> +        elif opt == '--target-arch':
> +            target_arch = arg
> +        elif opt == '--probe-prefix':
> +            probe_prefix = arg
> +
>          else:
>              error_opt("unhandled option: %s" % opt)
>  
> @@ -101,6 +119,19 @@ def main(args):
>  
>      kwargs = {}
>  
> +    if format == "stap":
> +        if binary is None:
> +            error_opt("--binary is required for SystemTAP tapset generator")
> +        if probe_prefix is None and target_type is None:
> +            error_opt("--target-type is required for SystemTAP tapset generator")
> +        if probe_prefix is None and target_arch is None:
> +            error_opt("--target-arch is required for SystemTAP tapset generator")
> +
> +        if probe_prefix is None:
> +            probe_prefix = ".".join([ "qemu", target_type, target_arch ])
> +    kwargs["binary"] = binary
> +    kwargs["probe_prefix"] = probe_prefix
> +
>      try:
>          tracetool.generate(sys.stdin, arg_format, arg_backend, **kwargs)
>      except tracetool.TracetoolError as e:
> diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
> index d8e5cdd..d21f88a 100644
> --- a/scripts/tracetool/__init__.py
> +++ b/scripts/tracetool/__init__.py
> @@ -167,6 +167,9 @@ def generate(fevents, format, backend, **options):
>      # fix strange python error (UnboundLocalError tracetool)
>      import tracetool
>  
> +    binary = options.pop("binary", None)
> +    probe_prefix = options.pop("probe_prefix", None)
> +
>      if len(options) > 0:
>          raise ValueError("unknown options: " + ", ".join(options))
>  
> @@ -188,6 +191,11 @@ def generate(fevents, format, backend, **options):
>          raise TracetoolError("backend '%s' not compatible with format '%s'" %
>                               (backend, format))
>  
> +    if backend == "dtrace":
> +        import tracetool.backend.dtrace
> +        tracetool.backend.dtrace.BINARY = binary
> +        tracetool.backend.dtrace.PROBEPREFIX = probe_prefix
> +
>      events = _read_events(fevents)
>  
>      if backend == "nop":
> diff --git a/scripts/tracetool/backend/dtrace.py b/scripts/tracetool/backend/dtrace.py
> new file mode 100644
> index 0000000..7c2051c
> --- /dev/null
> +++ b/scripts/tracetool/backend/dtrace.py
> @@ -0,0 +1,104 @@
> +#!/usr/bin/env python
> +# -*- coding: utf-8 -*-
> +
> +"""
> +DTrace/SystemTAP backend.
> +"""
> +
> +__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
> +__copyright__  = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
> +__license__    = "GPL version 2 or (at your option) any later version"
> +
> +__maintainer__ = "Stefan Hajnoczi"
> +__email__      = "stefanha@linux.vnet.ibm.com"
> +
> +
> +from tracetool import out
> +
> +
> +PUBLIC = True
> +
> +
> +PROBEPREFIX = None
> +
> +def _probeprefix():
> +    if PROBEPREFIX is None:
> +        raise ValueError("you must set PROBEPREFIX")
> +    return PROBEPREFIX
> +
> +
> +BINARY = None
> +
> +def _binary():
> +    if BINARY is None:
> +        raise ValueError("you must set BINARY")
> +    return BINARY
> +
> +
> +def c(events):
> +    pass
> +
> +
> +def h(events):
> +    out('#include "trace-dtrace.h"',
> +        '')
> +
> +    for e in events:
> +        out('''static inline void trace_%(name)s(%(args)s) {
> +    QEMU_%(uppername)s(%(argnames)s);
> +}
> +''' %
> +            {
> +                'name': e.name,
> +                'args': e.args,
> +                'uppername': e.name.upper(),
> +                'argnames': ", ".join(e.args.names()),
> +                })
> +
> +
> +def d(events):
> +    out('provider qemu {')
> +
> +    for e in events:
> +        args = e.args
> +
> +        # DTrace provider syntax expects foo() for empty
> +        # params, not foo(void)
> +        if args == 'void':

This fails. since args is now an Arguments instace. Fixed by changing
to:

+        if str(args) == 'void':

> +            args = ''
> +
> +        # Define prototype for probe arguments
> +        out('',
> +            'probe %(name)s(%(args)s);' %
> +            {
> +                'name': e.name,
> +                'args': args
> +                })
> +
> +    out('',
> +        '};')
> +
> +
> +def stap(events):
> +    for e in events:
> +        # Define prototype for probe arguments
> +        out('probe %(probeprefix)s.%(name)s = process("%(binary)s").mark("%(name)s")' %
> +            {
> +                'probeprefix': _probeprefix(),
> +                'name': e.name,
> +                'binary': _binary(),
> +                },
> +            '{')
> +
> +        i = 1
> +        if len(e.args) > 0:
> +            for name in e.args.names():
> +                # 'limit' is a reserved keyword
> +                if name == 'limit':
> +                    name = '_limit'
> +                out('  %s = $arg%d;' % (name.lstrip(), i))
> +                i += 1
> +
> +        out('}')
> +
> +    out()
> diff --git a/scripts/tracetool/format/d.py b/scripts/tracetool/format/d.py
> new file mode 100644
> index 0000000..a2d5947
> --- /dev/null
> +++ b/scripts/tracetool/format/d.py
> @@ -0,0 +1,20 @@
> +#!/usr/bin/env python
> +# -*- coding: utf-8 -*-
> +
> +"""
> +Generate .d file (DTrace only).
> +"""
> +
> +__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
> +__copyright__  = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
> +__license__    = "GPL version 2 or (at your option) any later version"
> +
> +__maintainer__ = "Stefan Hajnoczi"
> +__email__      = "stefanha@linux.vnet.ibm.com"
> +
> +
> +from tracetool import out
> +
> +
> +def begin(events):
> +    out('/* This file is autogenerated by tracetool, do not edit. */')
> diff --git a/scripts/tracetool/format/stap.py b/scripts/tracetool/format/stap.py
> new file mode 100644
> index 0000000..50a4c69
> --- /dev/null
> +++ b/scripts/tracetool/format/stap.py
> @@ -0,0 +1,20 @@
> +#!/usr/bin/env python
> +# -*- coding: utf-8 -*-
> +
> +"""
> +Generate .stp file (DTrace with SystemTAP only).
> +"""
> +
> +__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
> +__copyright__  = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
> +__license__    = "GPL version 2 or (at your option) any later version"
> +
> +__maintainer__ = "Stefan Hajnoczi"
> +__email__      = "stefanha@linux.vnet.ibm.com"
> +
> +
> +from tracetool import out
> +
> +
> +def begin(events):
> +    out('/* This file is autogenerated by tracetool, do not edit. */')
> 
>