Bryan wrote about a presentation he gave at Google (video) where he demo’ed DTrace in Python. While we did the dtrace probes for Ruby 1.8.5 and 1.8.6, I thought I’d show you how to do it on our Accelerators as well.

John Levon at Sun has written about the DTrace probes that he put into Python 2.4 before. So we have somewhere to start.

Let’s get Python 2.4.4 and the DTrace patch

mkdir /a/src/mkdir /a/1/languages/python244dcurl -O http://python.org/ftp/python/2.4.4/Python-2.4.4.tgztar zxvf Python-2.4.4.tgzcurl -O http://cvs.opensolaris.org/source/xref//jds/spec-files/trunk/patches/Python-07-dtrace.diff

The patch expects a directory call Python-new, so let’s create it

cp -R Python-2.4.4 Python-new

Let’s now apply the patch

gpatch -p0 < Python-07-dtrace.diff

The output of this working looks like

patching file Python-new/Include/frameobject.hpatching file Python-new/Makefile.pre.inpatching file Python-new/Objects/frameobject.cpatching file Python-new/Python/ceval.cpatching file Python-new/Python/phelper.dpatching file Python-new/Python/python.d

Move on in

cd Python-new/

Run configure

./configure --prefix=/a/1/languages/python244d --enable-shared

Now there’s going to be a couple of changes we’re going to make here so the thing builds, because if you type make && make install right now, it’ll fail. First in one way and then when you fix that, another.

Basically we have to bring the patch and Makefile up so that it’s a full 64-bit build (what our gcc compilers default to.

Open up the ustack helper file

nano Python/phelper.d

And take a look right at the top:

#define _SYS_STAT_H#include < stdio.h >#include "pyport.h"

And under the #include , add the two lines below

#define _SYS_STAT_H#include < stdio.h >#include < sys/socket.h >#include < sys/socketvar.h >#include "pyport.h"

Now the makefile

# Compiler optionsOPT=            -DNDEBUG -g -O3 -Wall -Wstrict-prototypesBASECFLAGS=      -fno-strict-aliasingCFLAGS=         $(BASECFLAGS) $(OPT)CPPFLAGS=       -I. -I$(srcdir)/IncludeLDFLAGS=LDLAST=SGI_ABI=CCSHARED=       -fPICLINKFORSHARED=

Add the -m64 flag to LDFLAGS

# Compiler optionsOPT=            -DNDEBUG -g -O3 -Wall -Wstrict-prototypesBASECFLAGS=      -fno-strict-aliasingCFLAGS=         $(BASECFLAGS) $(OPT)CPPFLAGS=       -I. -I$(srcdir)/IncludeLDFLAGS=        -m64LDLAST=SGI_ABI=CCSHARED=       -fPICLINKFORSHARED=

And finally we’ll add a -64 flag to each of the dtrace compile lines, so that you’re doing a 64-bit build all the way around.

So lines like

dtrace -o $@ -DPHELPER $(DFLAGS) $(CPPFLAGS) -C -G -s $(srcdir)/Python/phelper.d

Become

# grep dtrace MakefileDTRACE_OBJS=Python/dtrace.o Python/phelper.odtrace -o $@ -DPHELPER $(DFLAGS) $(CPPFLAGS) -C -G -64 -s $(srcdir)/Python/phelper.ddtrace -o $@ $(DFLAGS) -C -64 -h -s $(srcdir)/Python/python.dPython/dtrace.o: $(srcdir)/Python/python.d Python/ceval.odtrace -o $@ $(DFLAGS) -C -G -64 -s $(srcdir)/Python/python.d Python/ceval.o

Let’s build this bad-boy

makemake installln -s /a/1/languages/python244d /a/1/languages/python

Then we can take a simple dtrace script, like John Levon’s pywrites.d and see some stuff:

  libc.so.1`_write+0xa  libc.so.1`_dowrite+0×54  libc.so.1`_ndoprnt+0×2cb6  libc.so.1`fprintf+0×132  libpython2.4.so.1.0`Py_Main+0×48c  python`_start+0×6c    1  libc.so.1`_write+0xa  libc.so.1`_ndoprnt+0×3535  libc.so.1`fprintf+0×132  libpython2.4.so.1.0`Py_Main+0×48c  python`_start+0×6c    1

  libc.so.1`_write+0xa  libc.so.1`_fflush_u+0×34  libc.so.1`fclose+0×6b  libpython2.4.so.1.0`file_close+0xbf  libpython2.4.so.1.0`PyEval_EvalFrameReal+0×50c8    [ /a/1/languages/python244d/lib/python2.4/site-packages/django/core/management.py:803 (startproject) ]  libpython2.4.so.1.0`PyEval_EvalFrame+0×1f  libpython2.4.so.1.0`PyEval_EvalFrameReal+0×61dc    [ /a/1/languages/python244d/lib/python2.4/site-packages/django/core/management.py:1599 (execute_from_command_line) ]  libpython2.4.so.1.0`PyEval_EvalFrame+0×1f  libpython2.4.so.1.0`PyEval_EvalCodeEx+0×727  libpython2.4.so.1.0`PyEval_EvalFrameReal+0×5195    [ /a/1/languages/python244d/bin/django-admin.py:5 (?) ]  libpython2.4.so.1.0`PyEval_EvalFrame+0×1f  libpython2.4.so.1.0`PyEval_EvalCodeEx+0×727  libpython2.4.so.1.0`PyEval_EvalCode+0×36  libpython2.4.so.1.0`PyRun_FileExFlags+0×97  libpython2.4.so.1.0`PyRun_SimpleFileExFlags+0×16f  libpython2.4.so.1.0`Py_Main+0xac5  python`_start+0×6c    1  libc.so.1`_write+0xa  libc.so.1`_fflush_u+0×34  libc.so.1`fclose+0×6b  libpython2.4.so.1.0`file_close+0xbf  libpython2.4.so.1.0`PyEval_EvalFrameReal+0×50c8    [ /a/1/languages/python244d/lib/python2.4/site-packages/django/core/management.py:783 (_start_helper) ]  libpython2.4.so.1.0`PyEval_EvalFrame+0×1f  libpython2.4.so.1.0`PyEval_EvalCodeEx+0×727  libpython2.4.so.1.0`PyEval_EvalFrameReal+0×5195    [ /a/1/languages/python244d/lib/python2.4/site-packages/django/core/management.py:795 (startproject) ]  libpython2.4.so.1.0`PyEval_EvalFrame+0×1f  libpython2.4.so.1.0`PyEval_EvalFrameReal+0×61dc    [ /a/1/languages/python244d/lib/python2.4/site-packages/django/core/management.py:1599 (execute_from_command_line) ]  libpython2.4.so.1.0`PyEval_EvalFrame+0×1f  libpython2.4.so.1.0`PyEval_EvalCodeEx+0×727  libpython2.4.so.1.0`PyEval_EvalFrameReal+0×5195    [ /a/1/languages/python244d/bin/django-admin.py:5 (?) ]  libpython2.4.so.1.0`PyEval_EvalFrame+0×1f  libpython2.4.so.1.0`PyEval_EvalCodeEx+0×727  libpython2.4.so.1.0`PyEval_EvalCode+0×36  libpython2.4.so.1.0`PyRun_FileExFlags+0×97  libpython2.4.so.1.0`PyRun_SimpleFileExFlags+0×16f  libpython2.4.so.1.0`Py_Main+0xac5  python`_start+0×6c    3

[jason:/tmp] root# ls jason/init.py manage.py settings.py urls.py

I think I’m going to bring the patch up to Python 2.5 as well.