On 7 October 2011 18:08, Maciej Fijalkowski <fij...@gmail.com> wrote:
> On Fri, Oct 7, 2011 at 7:04 PM, Michael Foord <fuzzy...@gmail.com> wrote: > > > > > > On 7 October 2011 17:50, Maciej Fijalkowski <fij...@gmail.com> wrote: > >> > >> On Fri, Oct 7, 2011 at 1:33 PM, Igor Katson <igor.kat...@gmail.com> > wrote: > >> > When I first started benchmarking one of my Django sites, > >> > http://trip-travel.ru/ (using postgres driver pypq), > >> > I was disappointed by the results. PyPy was visually much slower than > >> > cPython (I just looked at how the site loads in the browser) > >> > > >> > But today I got some incredible results, I finally made PyPy to work > >> > faster > >> > than cPython, and found out that it got faster after loading the page > >> > several hundred times with "ab" or "siege" > >> > > >> > Here a the results, of mean response time by querying the home page > with > >> > apache's "ab" (cPython 2.7.2, Django 1.3, PyPy 1.6.0), served with > >> > cherrypy > >> > wsgi server: > >> > > >> > After 10 requests (excluding the first request): > >> > cPython - 163.529 ms > >> > PyPy - 460.879 ms > >> > > >> > 50 request more: > >> > cPython - 168.539 > >> > PyPy - 249.850 > >> > > >> > 100 requests more: > >> > cPython - 166.278 ms > >> > PyPy - 131.104 > >> > > >> > 100 requests more: > >> > cPython - 165.820 > >> > PyPy - 115.446 > >> > > >> > 300 requests more: > >> > cPython - 165.543 > >> > PyPy - 107.636 > >> > > >> > 300 requests more: > >> > cPython - 166.425 > >> > PyPy - 103.065 > >> > >> Thanks for doing the benchmarks :) > >> > >> > > >> > As we can see, the JIT needs much time to warm up, but when it does, > the > >> > result is pretty noticeable. > >> > By the way, with psycopg2, the site responds for 155.766 ms in average > >> > (only > >> > 10 ms faster), so using PyPy with Django makes much sense for me. > >> > > >> > As for now, pypy cannot run with uWSGI, which I use in production, but > >> > maybe > >> > i'll switch to PyPy for production deployments if "PyPy + PyPQ + Some > >> > pure > >> > python WSGI server" suite will outperform (uWSGI + cPython + > psycopg2). > >> > Though, the need to load the page 500 times after each server reload > is > >> > not > >> > comfortable. > >> > >> I've heard people using gunicorn. Maybe this is a good try? Loading > >> the pages is indeed annoying, but you need to load it a couple times > >> for results not to be noticably slower :) We kind of know that the JIT > >> warmup time is high, but it's partly a thing to fix and partly an > >> inherent property of the JIT. > >> > > > > > > FWIW I shared this internally at Canonical, and whilst people were > impressed > > there was some concern that having substantially worse performance for > the > > first few hundred requests would a) be a showstopper and b) screw up > > metrics. The technique of deliberate warming immediately after restart is > > interesting, but it would be hard to hit all the code paths. > > > > I realise this is inherent in the way the jit works - but I thought it > was a > > response worth sharing. I also assured them that pre-warm-up performance > > would continue to improve as pypy improves. ;-) > > > > All the best, > > > > Michael Foord > > > > It's also true for anything based on JVM and I've *never* seen anyone > complain about it. The whole concept of a JIT is just "new" to python > world. Seriously, would actually anyone notice if first 50 requests > after restart take extra 200ms??? I'm not sure, my computer and my > internet connection both have hiccups of over 200ms. Note that many > code paths are common, which means that speed up is also shared. > I think you have a point and I've added your response to the internal discussion. Michael -- http://www.voidspace.org.uk/ May you do good and not evil May you find forgiveness for yourself and forgive others May you share freely, never taking more than you give. -- the sqlite blessing http://www.sqlite.org/different.html
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