Stefano, ok now I get it:
in Python you can write the statement before the condition. Brilliant!!!all fruits and vegetables <http://stackoverflow.com/questions/2802726/putting-a-simple-if-then-statement-on-one-line> or more coconuts <https://en.wikipedia.org/wiki/%3F:#Python>
Martin P.S. one more (and last) apology to the owfs list On 11/06/2015 02:33 PM, Martin Patzak (GMX) wrote:
On 11/06/2015 02:13 PM, Stefano Miccoli wrote:For the ‘ it was cut and paste but my mail likes to ameliorate my mail and distinguish between opening and closing quotes,Ok, I seePlease find the program snippet at https://gist.github.com/miccoli/3df5e84624b50cb070deI run the program with python3, where ‘print’ is a function, so the conditional expression xifCelsey is correct (see 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 statementfrom __future__ import print_function and everything should run smoothly. S.yes, that does the trick.mnm@vincent:~/M/_Linux/python/_mnms_tests$ python pyownet_run_out_of_sockets.pyIteration 0 Iteration 4096 Iteration 8192 Iteration 12288 Iteration 16384 Iteration 20480 Iteration 24576 Iteration 28672Iteration 32468 raised exception: [Errno 99] Cannot assign requested addressPS: 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)maybe this does not belong in the owfs mailing list, so I apologize and keep it short:I do not know much about much about Python, but I read somewhere that good python-code is like pseudo-codeso in that regard your one-liner is good Python after all.BUT: what does the None do in front of the if??? It is not readable at all to me.None if i % freq else print('Iteration {}'.format(i))On 06 Nov 2015, at 13:10, Martin Patzak (GMX) <martin.pat...@gmx.de <mailto: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.pyFile "pyownet_run_out_of_sockets.py", line 13 None if i % freq else print('Iteration {}'.format(i)) ^ SyntaxError: invalid syntaxsince I am not very familiar with python I do not find the error on the spot... maybe you can help me outbtw. 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 liketcp 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 16384Iteration 16977 raised exception: [Errno 49] Can't assign requested addressso 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> querying anon localhost production owserverpyownet: 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 thisis 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.py3pyownet: 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 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 accessAnd: server: port = 4304 # localhost:4304 LA151105 allow net accessAfter 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 listOwfs-developers@lists.sourceforge.net <mailto:Owfs-developers@lists.sourceforge.net>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------------------------------------------------------------------------------ _______________________________________________ Owfs-developers mailing listOwfs-developers@lists.sourceforge.net <mailto:Owfs-developers@lists.sourceforge.net>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------------------------------------------------------------------------------ _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
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