For the ‘ it was cut and paste but my mail likes to ameliorate my mail and distinguish between opening and closing quotes,
Please find the program snippet at https://gist.github.com/miccoli/3df5e84624b50cb070de I run the program with python3, where ‘print’ is a function, so the conditional expression x if C else y is correct (see https://docs.python.org/3/reference/expressions.html#conditional-expressions <https://docs.python.org/3/reference/expressions.html#conditional-expressions>) With python 2.7 ‘print’ is a statement, thus the syntax error. Under python 2.7 you can add, as the first statement from __future__ import print_function and everything should run smoothly. S. PS: not very pythonic and cryptic, but I prefer the one-liner print(mess_if_True) if C else print(mess_if_False) rather than if C: print(mess_True) else: print(mess_False) > On 06 Nov 2015, at 13:10, Martin Patzak (GMX) <martin.pat...@gmx.de> wrote: > > Stefano, > > I wanted to try your program, but I get an error message: > > mnm@vincent:~/M/_Linux/python/_mnms_tests$ python > pyownet_run_out_of_sockets.py > File "pyownet_run_out_of_sockets.py", line 13 > None if i % freq else print('Iteration {}'.format(i)) > ^ > SyntaxError: invalid syntax > > since I am not very familiar with python I do not find the error on the > spot... maybe you can help me out > > > btw. the line > > p = protocol.proxy(‘myowserver', persistent=False) > > there is a typo: the first ' after ( is not a ' but a ‘ - it's hard to see > here, but with syntax highlighting it is easy to spot ;o) > > Martin > > > On 11/06/2015 11:20 AM, Stefano Miccoli wrote: >> A proxy object with 'persistent=False'will bind and destroy a socket for >> each call to the owserver. (If you call 'netstat -t’ after the timing test >> you will see hundreds of lines like >> tcp 0 0 localhost:45494 localhost:4304 TIME_WAIT >> which is the debris that remains after you tear down a socket…) >> >> On the contrary with ‘persistent=True'a single socket is bound at the >> beginning of the transaction and reused for every subsequent owserver call. >> So 'persistent=False’ has a very small overhead (about 1ms) for each call. >> >> Somehow your figures are consistent with this interpretation: non-persistent >> overhead is a constant small delta with respect to persistent connection. >> Since your owserver is apparently much slower than the one which I run my >> tests, you have a smaller relative overhead. >> >> Usually I would not care about the persistent/non persistent thing, unless >> you are running out of available sockets. >> >> This program >> >> import itertools >> from pyownet import protocol >> >> p = protocol.proxy(‘myowserver', persistent=False) >> freq = 1 << 12 >> >> for i in itertools.count(): >> try: >> c = p.dir() >> except protocol.Error as exc: >> print('Iteration {0} raised exception: {1}'.format(i, exc)) >> break >> None if i % freq else print('Iteration {}'.format(i)) >> >> >> prints >> >> Iteration 0 >> Iteration 4096 >> Iteration 8192 >> Iteration 12288 >> Iteration 16384 >> Iteration 16977 raised exception: [Errno 49] Can't assign requested address >> >> so it is possible to run out of sockets, although this is a rather edgy >> situation, that I’ve never analysed in detail. >> >> S. >> >>> On 06 Nov 2015, at 02:26, Loren Amelang <lo...@pacific.net >>> <mailto:lo...@pacific.net>> wrote: >>> >>> On Thu, 05 Nov 2015 13:02:13 +0100, >>> Stefano Miccoli mo...@icloud.com <mailto:mo...@icloud.com> wrote: >>> ... >>>> Just a few numbers, collected with >>>> https://github.com/miccoli/pyownet/blob/master/test/timing.py >>>> <https://github.com/miccoli/pyownet/blob/master/test/timing.py> >>>> <https://github.com/miccoli/pyownet/blob/master/test/timing.py >>>> <https://github.com/miccoli/pyownet/blob/master/test/timing.py>> querying a >>>> non localhost production owserver >>> >>>> pyownet: ver. 0.8.2 >>>> proxy_obj: ownet server at ('10.48.74.112', 4304) >>>> server info: pid 2662, ver. unknown >>>> >>>> timeit: >>>> statement: proxy_obj.dir("/") >>>> number: 20 >>>> repetitions: 5 >>>> >>>> ** non persistent : 1.29 ms, 1.30 ms, 1.30 ms, 1.33 ms, 1.36 ms, >>>> ** persistent : 0.77 ms, 0.77 ms, 0.79 ms, 0.80 ms, 0.97 ms, >>> >>>> The figure reported here are time for a single call to the given method, >>>> computed as the average of 20 consecutive calls. (Please note that I read >>>> the cached temperature value? uncached is of course much slower, but this >>>> is due to 1-wire) >>> >>> >>> I was surprised by the timing numbers you posted. So I tried your test >>> script with my BBB installation... >>> >>> Running on the BBB with the owserver: >>> --- >>> ubuntu@arm:~/Lpkg$ python3 StefanoTimingTest.py3 >>> pyownet: ver. 0.8.2 >>> (/usr/local/lib/python3.4/dist-packages/pyownet/__init__.py) >>> proxy_obj: ownet server at ('127.0.0.1', 4304) >>> server info: pid 1243, ver. unknown >>> >>> timeit: >>> statement: proxy_obj.dir("/") >>> number: 20 >>> repetitions: 5 >>> >>> ** non persistent : 37.55 ms, 37.78 ms, 39.26 ms, 40.15 ms, 41.11 ms, >>> ** persistent : 36.22 ms, 36.41 ms, 36.62 ms, 37.10 ms, 38.26 ms, >>> --- >>> >>> >>> Running Python on an external Windows machine, one Wi-Fi hop from the BBB: >>> --- >>> C:\Users\Loren\Documents\Projects\Computing\BeagleBone Black\BBB >>> Projects\1-Wire\OWFS Python logging>python StefanoTimingTest.py3 >>> owserver://10.1.1.4:4304 <owserver://10.1.1.4:4304> >>> pyownet: ver. 0.8.2 (C:\Apps\Python33\lib\site-packages\pyownet\__init__.py) >>> proxy_obj: ownet server at ('10.1.1.4', 4304) >>> server info: pid 22210, ver. unknown >>> >>> timeit: >>> statement: proxy_obj.dir("/") >>> number: 20 >>> repetitions: 5 >>> >>> ** non persistent : 41.69 ms, 45.79 ms, 45.99 ms, 48.34 ms, 49.41 ms, >>> ** persistent : 42.26 ms, 44.03 ms, 45.68 ms, 45.69 ms, 46.03 ms, >>> --- >>> >>> >>> Between those two tests was a long learning session. For those who don't >>> know... >>> >>> In netstat, "0.0.0.0" addresses are accessible from outside machines, >>> 127.0.0.1 addresses are not! >>> >>> The localhost setting is in (at least) two places in /etc/owfs.conf: >>> ! server: server = 10.1.1.4:4304 # localhost:4304 LA151105 allow net access >>> And: >>> server: port = 4304 # localhost:4304 LA151105 allow net access >>> >>> After making those changes, I found "restart" does not notice them! You >>> have to use "force-reload": >>> ubuntu@arm:~/Lpkg$ sudo /etc/init.d/owserver force-reload >>> * Restarting 1-Wire TCP Server owserver >>> >>> Suddenly it works from out on the network! >>> >>> >>> So I wonder why persistence makes less than 10% difference here, while on >>> your much faster machine it makes 25 to 40%... >>> >>> | Loren Amelang | lo...@pacific.net <mailto:lo...@pacific.net> | >>> >>> >>> >>> >>> ------------------------------------------------------------------------------ >>> _______________________________________________ >>> Owfs-developers mailing list >>> Owfs-developers@lists.sourceforge.net >>> <mailto:Owfs-developers@lists.sourceforge.net> >>> https://lists.sourceforge.net/lists/listinfo/owfs-developers >>> <https://lists.sourceforge.net/lists/listinfo/owfs-developers> >> >> >> >> ------------------------------------------------------------------------------ >> >> >> _______________________________________________ >> Owfs-developers mailing list >> Owfs-developers@lists.sourceforge.net >> <mailto:Owfs-developers@lists.sourceforge.net> >> https://lists.sourceforge.net/lists/listinfo/owfs-developers >> <https://lists.sourceforge.net/lists/listinfo/owfs-developers> > > ------------------------------------------------------------------------------ > _______________________________________________ > Owfs-developers mailing list > Owfs-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/owfs-developers
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