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Variable fetch optimization

php.internals

Andi Gutmans

21 years ago

Hi,

Attached is a patch to optimize variable fetches (basically it caches the
fetches so that variables aren't re-fetched every time, most noticeable in
loops with the loop control counter but also it's a general improvement).
It's similar to the patch Sterling and Thies did a year ago in their
optimization patch.
As compiling the zend_execute.c file is starting to take a long time
(minutes) due to inlining with the goto VM architecture, I suggest to apply
Zend.m4 to make the default the function handler paradigm. The performance
difference is not big and it'll make it easier to work on PHP. For
production environments one can use a configure switch to turn this on.
I'd
be happy to hear of benchmarks.

In general, there might be problems with extensions which access the active
symbol table directly. It's something I still need to look into so please
report any problems.

Please try and take some time to test it.

Andi

Andi Gutmans

21 years ago

http://snaps.php.net/~andi/Zend.m4.diff.gz
http://snaps.php.net/~andi/cv.diff.gz

At 09:31 AM 10/1/2004 -0700, Andi Gutmans wrote:

Thies C. Arntzen

21 years ago

before: 34.430
after: 20.126

do i need to say more?

(if it really works, which i haven't tested yet)

great andi!
re,
tc

PS: i really think that the vm should be generated by a script! looking
at what makes most of the patch i really think that we're making
hacking the engine more complex than needed.

On 2004-10-01 18:31:37 +0200, Andi Gutmans <andi@zend.com> said:

Andrei Zmievski

21 years ago

On Sat, 02 Oct 2004, Thies C. Arntzen wrote:

> PS: i really think that the vm should be generated by a script! looking
> at what makes most of the patch i really think that we're making
> hacking the engine more complex than needed.

I agree..

- Andrei

Wez Furlong

21 years ago

I'm a big fan of making the computer do the work on our behalf (that's
what it's there for, right?).

It shouldn't be a huge problem to write a php script to generate the
different executors from a source file.  If you're worried about
bootstrapping, we can keep the generated files in CVS and/or bundle
them pre-generated in the distro.

--Wez.


On Wed, 6 Oct 2004 13:36:38 -0700, Andrei Zmievski
<andrei@gravitonic.com> wrote:

Sterling Hughes

21 years ago

Wez Furlong wrote:

>I'm a big fan of making the computer do the work on our behalf (that's
>what it's there for, right?).
>
>It shouldn't be a huge problem to write a php script to generate the
>different executors from a source file.  If you're worried about
>bootstrapping, we can keep the generated files in CVS and/or bundle
>them pre-generated in the distro.
>
>

Yeah, actually Dmitry wrote a script that converted the old executor
into the new executor, so the script was already there.  I think its
that Andi doesn't like the concept (I do like the concept btw), not the
work involved.  Personally, I'd prefer to see the executor generated, so
long as the source format is well thought-out.  Cause it will allow us
to do things like, for example, generating an x86 JIT.

-Sterling

Andi Gutmans

21 years ago

At 03:15 PM 10/6/2004 -0700, Sterling Hughes wrote:

>Yeah, actually Dmitry wrote a script that converted the old executor into
>the new executor, so the script was already there.  I think its that Andi
>doesn't like the concept (I do like the concept btw), not the work
>involved.  Personally, I'd prefer to see the executor generated, so long
>as the source format is well thought-out.  Cause it will allow us to do
>things like, for example, generating an x86 JIT.

I actually liked the concept too :) (my initial prototype was a script). I
agree that the macro's aren't that easy to handle.
We're working on doing this with a script now, which means that it'll be
easier to see what's going on (the script will be slightly harder to
maintain but it's probably worth it).
We might need to keep the generated files in CVS but that shouldn't be a
problem.

Andi

Andi Gutmans

21 years ago

At 12:44 PM 10/2/2004 +0200, Thies C. Arntzen wrote:

>before: 34.430
>after: 20.126
>
>do i need to say more?
>
>(if it really works, which i haven't tested yet)

Made another fix (we had to take care of global variables being messed with
by extensions).

>PS: i really think that the vm should be generated by a script! looking at
>what makes most of the patch i really think that we're making hacking the
>engine more complex than needed.

I am not sure. There are advantages and disadvantages to both.

pre-processor vs. script
Advantage: Only maintain source and not script (which might be icky), no
pre-build scripts (which might be a PITA on platforms like Windows), no
script portability issues
Disadvantages: More magic in the source code itself, might be slightly
harder to debug.

Frankly, I am not sure what's better. I think it might be a good idea to
see what can be done with a script and then compare. Will look into it.

Andi