On 29/07/2013 21:33, Sven Van Caekenberghe wrote:
Chris,
On 29 Jul 2013, at 20:52, Chris <cpmbailey@btinternet.com> wrote:
I've been getting a little concerned with certain aspects of performance recently. Just a couple of examples off the top of my head were trying to do a printString on 200000 floats which takes over 3 seconds. If I do the same in Python it is only 0.25 seconds. Similarly reading 65000 points from a database with the PostgresV2 driver was about 800m/s and only 40 with psycopg. I'd have to try it again but am pretty sure going native was faster than OpenDBX as well. I appreciate Pharo is never going to be able to compete with the static-typed heavyweight languages but would hope we can get performance at least comparable to other dynamic languages :) Is it just that some method implementations are in need of some TLC; more things moved on top of C libraries and primitives and so forth rather than anything with the VM itself?
Cheers Chris You could try:
| floats | floats := (1 to: 200000) collect: #asFloat. [ FloatPrintPolicy value: InexactFloatPrintPolicy new during: [ String new: 1500000 streamContents: [ :stream | floats do: [ :each | each printOn: stream ] ] ] ] timeToRun
=> 796 ms
I haven't looked at the Postgresql driver in detail, but I would guess that PostgresV2 reads from a String somewhere, which is slow unless care is taken, while psycopg probably does a binary read. That last thing can be done in Pharo as well, but not if the driver is text based somehow.
You are right: Pharo should definitively be in the same range as other dynamically typed languages. But dynamic languages are dangerous: user become lazy / ignorant about performance.
Thanks for pushing this.
Sven
-- Sven Van Caekenberghe http://stfx.eu Smalltalk is the Red Pill
Thanks for the float tip :) I think I need to investigate the Postgres thing a bit further. I thought it was a fairly native driver but the double array type may well be using a string