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extradoc / minute / pypy-sync-2005-08-11.txt

pypy-sync developer meeting 11th August 2005

Time & location: 1pm (30 minutes) at #pypy-sync 


         Samuele Pedroni, 
         Adrien Di Mascio, 
         Ludovic Aubrien,
         Carl Friedrich Bolz, 
         Niklaus Heidimann,
         Eric van Riet Paap,
         Holger Krekel (minutes/moderation)
         later: Richard Emslie, Michael Hudson, 
                Armin Rigo, Christian Tismer 

with pre info::
        Anders Lehmann

Regular Topics 

- roll call. holger opens the meeting. 

- activity reports (3 prepared lines of info). 
  All Attendees submitted activity reports (see `IRC-Log`_ 
  at the end and 'LAST/NEXT/BLOCKERS' entries in particular)

- resolve conflicts/blockers
  No direct conflicts were discovered. Compliancy work was
  discussed under its own topic. 

Topics of the week

re / array status

Niklaus reports that _sre is feature-complete and passes 
compliance tests.  It's running mostly at application leve
and is thus quite slow.  Niklaus is moving bits and pieces
to interpreter-level but it is not clear how the main
dispatching loop could be transformed this way (and especially
making it non-norecursive).  Advice and comments welcome. 
Niklaus will basically not be available until the Heidelberg sprint. 

Niklaus also reports that the array module is passing
the tests but lives fully at applevel. An open question
is how C data type sizes are modeled in PyPy.  Samuele
notes that this depends on how we plan to interact
with user extensions.  It is agreed that this particular
data-type size question is a post-0.7 issue. 

llvm status

Eric reports that the llvm is progressing steadily.  There are
currently 10 exception raising operations left to implement. 
Also some external (suggested_primitive) functions need to 
be implemented as well as 64 bit support.  The benchmarks
richards and bpnn can produce standalone executables 

While working on the llvm backend, three bugs in the LLVM 
tool chain itself were discovered, reported and fixed by
the LLVM guys very quickly.  The current llvm file 
can be found at http://codespeak.net/~ericvrp/download. 
Eric thinks that a PyPy standalone version based on LLVM 
is not far away!  Everybody agrees that next week it would
make sense to plan an LLVM track (among other tracks) 
for the Heidelberg sprint. 

GC and threading 

Two important aspects of the translated PyPy version 
regard Garbage Collection and Threading.  We planned
for having both GC and threading implemented as
translation aspects.  While Carl is working on GC 
(during his SoC project) we have no translation-aspect 
code yet regarding threading integration. 

Carl reports that the pure simulator already works. 
There is an Address class that provides raw access
to memory which should be used by the actual GC implementations. 
This class is annotated with SomeAddress. On top of
this is the 'lltypesimulator', a class that behaves
like the _ptr type of pypy/rpython/lltype.  Next
is implementing GC hooks into the llinterp and
then actually writing GC implementations. 
An open issue is that the rtyper/specializer needs 
to be extended to work with the new GC classes. 

Regarding threading there are various aspects
where discussion started: 

- support for "import thread" and the according API 
  at Python level could be regarded as a different
  issue than providing new (stackless) threading techniques. 
  However, it's probably also possible (Armin thinks) 
  to offer this API on top of a stackless implementations. 

- threading support at the moment is (according to
  Samuele) more about how we can weave translation
  aspects into the translation machinery.  Samuele
  also emphasizes that supporting os-level threads means
  quite some debugging work, also judging from Jython
  experiences which offers free threading. 

more discussion is scheduled to happen at the technical
board meeting friday 12th August and probably best 
more on pypy-dev itself (see Armin's `posting`_ and the
ensuing thread). 

.. _posting: http://codespeak.net/pipermail/pypy-dev/2005q3/002257.html

FYI: codespeak migration status

The migration of codespeak.net got postponed because the
target machine's network connectivity is not satisfying yet
(latency and dropped packets problems).  However, commits
are now mirrored to the new machine which is basically
ready to take over in case the current machine gets problems. 
It's possible that the services get migrated without
prior announcements (unless people really think it's
neccessary to pre announce that accordingly). 

This issue was postponed due to time restrictions 
but it was mostly informational anyway. 


Holger closes the meeting in time at 13:30pm. 

.. _`IRC-log`:

Here is the full IRC log:: 

    Aug 11 12:40:10 -->	You are now talking on #pypy-sync
    Aug 11 13:00:51 <hpk>	ok, let's start? 
    Aug 11 13:01:01 <cfbolz>	yes
    Aug 11 13:01:08 <hpk>	here is the agenda: 
    Aug 11 13:01:11 <hpk>	- roll call.
    Aug 11 13:01:11 <hpk>	- activity reports (3 prepared lines of info).
    Aug 11 13:01:11 <hpk>	- resolve conflicts/blockers
    Aug 11 13:01:11 <hpk>	*Topics of the week*
    Aug 11 13:01:11 <hpk>	- re / array status
    Aug 11 13:01:11 <hpk>	- llvm status
    Aug 11 13:01:11 <hpk>	- GC and threading
    Aug 11 13:01:11 <hpk>	- codespeak migration status
    Aug 11 13:01:27 <hpk>	i propose the following order for activity reports: 
    Aug 11 13:01:33 <hpk>	arigo, aleale, hpk, adim, cfbolz, ericvrp, nik, pedronis
    Aug 11 13:01:44 ---	You are now known as arigo
    Aug 11 13:01:50 <arigo>	DONE: random small stuff; mostly done: proper exc handling in rtyper
    Aug 11 13:01:50 <arigo>	NEXT: to be decided on the technical board meeting
    Aug 11 13:01:50 <arigo>	BLOCKERS: -
    Aug 11 13:01:56 <ludal>	hi
    Aug 11 13:01:59 ---	You are now known as aleale
    Aug 11 13:02:05 <aleale>	PREV: Compliance tests
    Aug 11 13:02:05 <aleale>	NEXT: Compliance tests
    Aug 11 13:02:05 <aleale>	BLOCKERS: None
    Aug 11 13:02:31 <aleale>	too many nick changes :-) 
    Aug 11 13:02:36 <aleale>	adim, can you continue? 
    Aug 11 13:02:40 <adim>	LAST: astbuilder (starting to have good results)
    Aug 11 13:02:40 <adim>	NEXT: holidays
    Aug 11 13:02:40 <adim>	BLOCKERS: none
    Aug 11 13:02:49 ---	You are now known as hpk
    Aug 11 13:03:00 <hpk>	LAST: codespeak.net migration, mentoring/user support
    Aug 11 13:03:00 <hpk>	NEXT: some more codespeak-migration, open issues, at least three non-pypy days
    Aug 11 13:03:00 <hpk>	BLOCKERS: None
    Aug 11 13:03:16 <ludal>	PREV: none/helping adrien
    Aug 11 13:03:17 <ludal>	NEXT: not much more
    Aug 11 13:03:17 <ludal>	BLOCKERS: none
    Aug 11 13:03:35 <cfbolz>	LAST: polished my lltype implementation on top of the memory simulation: it works quite well now (only 9 tests of all tests that use llinterp fail)
    Aug 11 13:03:35 <cfbolz>	NEXT: implement a GC for the llinterp
    Aug 11 13:03:35 <cfbolz>	BLOCKERS: None
    Aug 11 13:03:45 <ericvrp>	last: progressing on full pypy translation with llvm
    Aug 11 13:03:46 <ericvrp>	next: finishing external functions and exception raising operations
    Aug 11 13:03:48 <ericvrp>	issues: possibly other llvm bugs
    Aug 11 13:03:55 <nik>	LAST: _sre and array tuning
    Aug 11 13:04:00 <nik>	NEXT: not much, will be at a conference in brussels from sunday until the sprint
    Aug 11 13:04:04 <nik>	BLOCKERS: none
    Aug 11 13:04:22 <pedronis>	Last: 2.4.1 tests, open issues, float ops/math and errors, a bit of tracker gardening, slottified lltype
    Aug 11 13:04:24 <pedronis>	Next: ll_math.h error handling, ?
    Aug 11 13:04:25 <pedronis>	Blockers: -
    Aug 11 13:04:38 <hpk>	ok, thanks, there seems to be no blockers ... 
    Aug 11 13:04:50 <cfbolz>	except llvm bugs :-(
    Aug 11 13:04:59 <hpk>	and except that some of the compliance work was a bit re-recommiting
    Aug 11 13:05:08 <hpk>	but we can talk about this at the sprint or some other time i think
    Aug 11 13:05:23 <hpk>	so on to the next topic: re / array status
    Aug 11 13:05:29 -->	rxe (n=rxe@client-82-14-80-179.manc.adsl.virgin.net) has joined #pypy-sync
    Aug 11 13:05:33 <rxe>	hi
    Aug 11 13:05:33 <nik>	ok
    Aug 11 13:05:41 <nik>	_sre is feature-complete and fully compliant
    Aug 11 13:05:47 <hpk>	rxe: we are in re/array status
    Aug 11 13:05:49 <nik>	only problem: it's very slow ;)
    Aug 11 13:06:03 <nik>	i'm slowly migrating some code to interp-level to improve that
    Aug 11 13:06:11 <hpk>	but the core is running at applevel still? 
    Aug 11 13:06:16 <nik>	yes
    Aug 11 13:06:22 <hpk>	(i am not too accustomed to how re works internally)
    Aug 11 13:06:36 <nik>	the core dispatcher loop is at app-level
    Aug 11 13:06:50 <hpk>	you basically have a plan how to put this to interp level? 
    Aug 11 13:07:00 <nik>	no
    Aug 11 13:07:03 <nik>	it might be hard
    Aug 11 13:07:09 <nik>	to do it non-recursive
    Aug 11 13:07:20 <nik>	but not impossible
    Aug 11 13:07:34 <hpk>	so would you need some helping advices from your mentors? 
    Aug 11 13:07:55 <nik>	yes
    Aug 11 13:08:06 <nik>	i think this is best discussed at the sprint
    Aug 11 13:08:12 -->	mwh (N=user@82-33-185-193.cable.ubr01.azte.blueyonder.co.uk) has joined #pypy-sync
    Aug 11 13:08:14 <nik>	as i will not have much time to work on it before that anyway
    Aug 11 13:08:17 <hpk>	ok, especially since you will be away since then 
    Aug 11 13:08:18 <hpk>	right
    Aug 11 13:08:24 <hpk>	then a few words about array? 
    Aug 11 13:08:42 <hpk>	mwh: hi, we are in the re/array topic already 
    Aug 11 13:08:42 <nik>	array is also compliant
    Aug 11 13:08:51 <nik>	fully app-level at the moment
    Aug 11 13:09:00 <mwh>	(i'm late and also only planning on lurking sorry)
    Aug 11 13:09:00 <nik>	there are conceptual issues:
    Aug 11 13:09:18 <nik>	do we respect a machine's C data type sizes?
    Aug 11 13:09:24 <nik>	ie the bytesize of a short int?
    Aug 11 13:09:41 <nik>	or is pypy like a vm with fixed data type sizes?
    Aug 11 13:09:56 <nik>	currently sizes are fixed, both in array and in struct
    Aug 11 13:10:08 <hpk>	good question, pedronis, do you happen to have an opinion on that?
    Aug 11 13:10:23 <pedronis>	well, the fact is that those aspects are related to interaction with other ext (possibly user) modules
    Aug 11 13:10:44 <pedronis>	so until we have a model for that is hard to answer
    Aug 11 13:10:46 <nik>	yes. if a user dumps arrays to disk from CPython
    Aug 11 13:10:54 <nik>	and tries to read them with pypy's array
    Aug 11 13:10:58 <nik>	stuff can break at the moment
    Aug 11 13:11:14 <nik>	but it's a hard problem as array/struct assume a C backend
    Aug 11 13:11:17 -->	arigo (n=odie@bch-ma-195.epfl.ch) has joined #pypy-sync
    Aug 11 13:11:18 <hpk>	i guess we should treat this question as a post-0.7 issue
    Aug 11 13:11:27 <pedronis>	yes
    Aug 11 13:11:39 <hpk>	arigo: we are at the end of the re/array topic
    Aug 11 13:11:53 <hpk>	ok, thanks Niklaus, then next topic: llvm status, eric? 
    Aug 11 13:12:03 <hpk>	(or rxe for that matter)
    Aug 11 13:12:06 <ericvrp>	this is my prepared text:
    Aug 11 13:12:07 <ericvrp>	The LLVM backend is progressing slowly but steadily.  We currently have about 10 exception raising operations todo,
    Aug 11 13:12:09 <ericvrp>	which is straightforward. The other open issue is the handful of external (suggested_primitive) functions that need
    Aug 11 13:12:10 <ericvrp>	to be implemented. After a standalone version works, we need to refactor (of
    Aug 11 13:12:12 <ericvrp>	course) and make the thing work on 64bit machines as well.
    Aug 11 13:12:13 <ericvrp>	The benchmarks bpnn and Richards produce standalone executables already. (python llvm2/demo/richards l)
    Aug 11 13:12:15 <ericvrp>	We encountered three bugs in the LLVM toolchain which after being reported to the LLVM team were all fixed very quickly. Which, in a way, gives me a good feeling. But discovering, reporting and waiting for fixes/workaround is what is costing us most of the time currently. I hope to have a working standalone mid next-week. 
    Aug 11 13:12:17 <ericvrp>	The current llvm file can be found at http://codespeak.net/~ericvrp/download
    Aug 11 13:12:58 <hpk>	wow, i am impressed with the progress
    Aug 11 13:13:07 <cfbolz>	me as well. very cool!
    Aug 11 13:13:31 <hpk>	and you reported some 3 times being faster on richards/bpnn, right? 
    Aug 11 13:13:52 <ericvrp>	the only progress that counts (pypy) is still to come and I am not 100% sure if that will work first time round as did the C backend
    Aug 11 13:14:07 <hpk>	well, the C backend didn't work exactly first time around :-) 
    Aug 11 13:14:17 <ericvrp>	about the speed: I don't know if the C backend does any gcc optimizations currently?!?
    Aug 11 13:14:28 <ericvrp>	richard?
    Aug 11 13:14:31 <rxe>	hpt: I think I reported the speed increase.
    Aug 11 13:14:37 <rxe>	hpk
    Aug 11 13:14:45 <hpk>	ericvrp: the 337 pystones where with -O2 i think
    Aug 11 13:15:02 <ericvrp>	I have seen no llvm pystone benchmark results
    Aug 11 13:15:09 <cfbolz>	and for richard/bpnn?
    Aug 11 13:15:16 <rxe>	however i had modify bpnn to get speed increases
    Aug 11 13:15:31 <rxe>	for/range to while loops
    Aug 11 13:15:35 <hpk>	ah, ok, nevermind, that's not too important right now but interesting neverhteless 
    Aug 11 13:15:49 <hpk>	feel free to report any breakthroughts to pypy-dev, please 
    Aug 11 13:16:03 <ericvrp>	ok
    Aug 11 13:16:08 <rxe>	:-)
    Aug 11 13:16:09 <hpk>	i think it will make sense to have a "llvm" track at the heidelberg sprint
    Aug 11 13:16:26 <rxe>	yes - I would like to see some unification of the backends
    Aug 11 13:16:39 <hpk>	indeed, we should discuss this next week in some detail, i think
    Aug 11 13:16:39 <rxe>	with the external functions and test esp
    Aug 11 13:16:49 <rxe>	ok
    Aug 11 13:16:56 <ericvrp>	yes -
    Aug 11 13:17:18 <hpk>	ok, let's rush to the next topic: GC and threading
    Aug 11 13:17:28 <hpk>	there is a mail from armin on pypy-dev 
    Aug 11 13:17:43 <hpk>	and carl, can you say a few words regarding GC and how it is supposed to integrate into PyPy? 
    Aug 11 13:17:56 <cfbolz>	I am not that far yet :-(
    Aug 11 13:18:02 <cfbolz>	I did some groundwork, and hope that I can now actually start to work writing GCs
    Aug 11 13:18:07 -->	stakkars (i=mtsnwcw@i528C1380.versanet.de) has joined #pypy-sync
    Aug 11 13:18:19 <hpk>	cfbolz: so you are at the pure simulator still 
    Aug 11 13:18:27 <cfbolz>	there is an Address class that provides raw access to memory and should be used by the GC implementation. this class is annotated with SomeAddress
    Aug 11 13:18:35 <cfbolz>	hpk: yes
    Aug 11 13:18:40 <cfbolz>	there is a memory simulator that simulates the address' behaviour
    Aug 11 13:18:52 <cfbolz>	on top of this there is the lltypesimulator: a class that behaves like the _ptr  type of lltype
    Aug 11 13:19:17 <cfbolz>	the next thing I'm doing is imeplemting GC hooks into the llinterp for the 
    Aug 11 13:19:29 <cfbolz>	and then actually write a GC
    Aug 11 13:19:37 <cfbolz>	there is still quite some stuff left:
    Aug 11 13:19:56 <cfbolz>	the rtyper has to be extended to work with the GC stuff
    Aug 11 13:20:13 <cfbolz>	plus some more unsolved problems
    Aug 11 13:20:30 <hpk>	i see, but i guess you are in consultation with Samuele there
    Aug 11 13:20:37 <cfbolz>	of course
    Aug 11 13:21:14 <hpk>	ok, arigo, and all, i have a question regarding threading
    Aug 11 13:21:14 <cfbolz>	one other problem:
    Aug 11 13:21:21 <cfbolz>	no go on
    Aug 11 13:21:40 <hpk>	doesn't it make sense to divide the discussion into "import thread" support and "new threading facilities"? 
    Aug 11 13:22:15 <hpk>	i mean we do need to offer the thread module, and e.g. stackless ideas or having multiple object spaes is a different issue, isn't it? 
    Aug 11 13:22:32 <stakkars>	yes
    Aug 11 13:23:24 <hpk>	arigo, pedronis: i am fine with raising and discussing this on pypy-dev, though, if further immediate comments cannot be made
    Aug 11 13:23:34 <pedronis>	well, you could hava import thread threads as user level threads
    Aug 11 13:23:58 <stakkars>	too bad that I missed the begining
    Aug 11 13:24:11 <hpk>	pedronis: but that might already violate assumptions regarding compliancy? 
    Aug 11 13:24:34 <hpk>	stakkars: this is just the first discussion, more to follow and the pypy-dev thread is there as well
    Aug 11 13:24:40 <pedronis>	I don't think that threadidng is a compliancy problem
    Aug 11 13:24:52 <pedronis>	is more about showing what translating can achieve
    Aug 11 13:24:58 <pedronis>	at the moment
    Aug 11 13:24:58 <stakkars>	nor do I. It is an option which can be turned off
    Aug 11 13:25:19 <hpk>	pedronis: i see the point but i am not sure i 100% agree
    Aug 11 13:25:39 <arigo>	hpk: I think we can emulate the thread module with stackless translation
    Aug 11 13:25:59 <arigo>	just by switching tasklets automatically every N bytecodes
    Aug 11 13:26:21 <hpk>	maybe
    Aug 11 13:26:25 <pedronis>	well, supporting os threads means potentially quite some debugging
    Aug 11 13:26:35 *	hpk notes 4 minutes left
    Aug 11 13:26:35 <stakkars>	yes, I think so, too. I did some tests and theoretical musings.
    Aug 11 13:26:37 <pedronis>	threads are not nice that way
    Aug 11 13:26:48 <stakkars>	may I drop my 3 lines?
    Aug 11 13:26:56 <hpk>	yes
    Aug 11 13:27:01 <rxe>	cant we introduce OS threads and GIL except for IO?
    Aug 11 13:27:02 <pedronis>	Jython has free
    Aug 11 13:27:23 <stakkars>	DONE: integrated the new marshal module. Wrote exact string_to_float, moved it to interp-level, did some tests and theory about how to stackless
    Aug 11 13:27:32 <stakkars>	NEXT: write a book chapter on PyPy
    Aug 11 13:27:39 <stakkars>	BLOCK: time consumption due to memory fotprint and swapping, hard to track side effects of certain statements on the annotator
    Aug 11 13:28:05 <hpk>	ok, let's continue gc+threading at pypy-dev and at the technical board meeting, last topic (3 minutes left) 
    Aug 11 13:28:10 <pedronis>	Jython has free threading but is all quite delicate
    Aug 11 13:28:19 <stakkars>	the blocker is muc better since I pushed arigo/pedronis to slotify
    Aug 11 13:28:40 <hpk>	codespeak.net migration is half-done
    Aug 11 13:28:48 <pedronis>	well, slottifying lltype killed 150m of memory usage
    Aug 11 13:28:56 <hpk>	svn commits are mirrored to code2.codespeak.net seconds after the commit on the main hosts happens
    Aug 11 13:29:01 <stakkars>	yes, I noticed.
    Aug 11 13:29:08 <pedronis>	I don't know what happens combined with compacting node.py
    Aug 11 13:29:20 *	hpk stops with the topic
    Aug 11 13:29:37 <hpk>	stakkars, pedronis: are you reading my comments? 
    Aug 11 13:29:48 <stakkars>	where?
    Aug 11 13:29:54 <cfbolz>	here
    Aug 11 13:29:57 <hpk>	well, i tried to move to the next topic
    Aug 11 13:30:04 <hpk>	but you conitnued with the old topic 
    Aug 11 13:30:04 <stakkars>	which is it
    Aug 11 13:30:13 <hpk>	pypy-sync has a very tight schedule
    Aug 11 13:30:35 <hpk>	in fact, the meeting is closed now
    Aug 11 13:30:54 <hpk>	it
    Aug 11 13:31:09 <hpk>	pypy-sync is just for synchronisation not for full blown content discussions
    Aug 11 13:31:13 *	stakkars wonders why hpk wasted the rest instead of moving on
    Aug 11 13:31:35 *	pedronis to make his point
    Aug 11 13:32:26 <rxe>	can i post 3 lines (sorry I was late)?
    Aug 11 13:32:29 <rxe>	DONE: tiny llvm stuff
    Aug 11 13:32:29 <rxe>	NEXT: llvm refactors / organise sprint travelling
    Aug 11 13:32:29 <rxe>	BLOCKERS: new laptop
    Aug 11 13:33:01 <hpk>	thanks, i'll add it to the minutes
    Aug 11 13:33:16 <cfbolz>	bye
    Aug 11 13:33:20 <hpk>	see you
    Aug 11 13:33:21 <stakkars>	bye
    Aug 11 13:33:22 <adim>	bye
    Aug 11 13:33:24 <mwh>	bye
    Aug 11 13:33:24 <rxe>	bye
    Aug 11 13:33:25 <ericvrp>	bye
    Aug 11 13:33:30 <ludal>	bye
    Aug 11 13:33:35 <--	mwh (N=user@82-33-185-193.cable.ubr01.azte.blueyonder.co.uk) has left #pypy-sync ("ERC Version 5.0 (CVS) $Revision: 1.767 $ (IRC client for Emacs)")
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