Good tips. Thanks! I'll improve them and post as soon as they're ready. Moreover I was thinking that it might be nice to just modify Django to use namedtuples and see how will that influence execution. The problem is that it might be difficult to create reliable tests. If you think that there is anything more missing please let me know.
W dniu poniedziałek, 24 lutego 2014 03:01:07 UTC+1 użytkownik Alex_Gaynor napisał: > > FWIW these benchmaks are not measuring accurately. Creating a tuple of the > form "(1, 2, 3)" (notably, where all the members are literal constants) > takes NO time actually, since it's an immutable container of all immutable > items, the compiler is able to factor the work out. A benchmark, even as > idiotically simple as: > > "a = 1; (1, 2, a)" would more accurately mirror the real world. > > Alex > > > On Sun, Feb 23, 2014 at 7:57 PM, Russell Keith-Magee < > [email protected] <javascript:>> wrote: > >> >> Hi Stratos, >> >> Thanks for providing those benchmarks -- that's really helpful. >> >> However, It's all well and good to say that "Doing X takes 0.01s" or "X >> is 50% slower than Y", but that if the time taken to do X is incredibly >> small to start with, a 50% slowdown doesnt really matter that much. The >> fact that namedtuple is slower than tuple is clear from your data; what >> isn't clear is how much we should be concerned. Unfortunately, the raw time >> data doesn't tell us how fast or slow your test machine is. >> >> If you can provide a baseline for comparison, that would be very helpful. >> In the past when we've done benchmarks, we've used: >> >> * Invoking a no-op (i.e., pass) >> * Invoking a function that performs a no-op. >> >> This essentially gives us an indication for the order of magnitude of the >> time values you've provided, and allows us to say "creating a named tuple >> has the same overhead as a single function call", (or 10 function calls, or >> whatever is appropriate). This puts the benchmark into concrete terms - >> nobody would do a code review and say "you need to remove 1 function call >> for speed purposes", but they might say "these 1000 function calls seem >> excessive". >> >> Yours, >> Russ Magee %-) >> >> >> On Sun, Feb 23, 2014 at 2:01 AM, Stratos Moros <[email protected]<javascript:> >> > wrote: >> >>> Completely unscientific microbenchmarks: >>> (gist<https://gist.github.com/stratoukos/dcde41ee0903dcdd577a> >>> ) >>> >>> >>> from timeit import Timer >>> >>> ## creation >>> # tuple >>> >>> Timer('(1, 2, 3, 4, 5)').timeit() >>> 0.02694106101989746 >>> >>> # namedtuple with args >>> >>> Timer('T(1, 2, 3, 4, 5)', setup=''' >>> from collections import namedtuple >>> T = namedtuple("T", "a b c d e")''' >>> ).timeit() >>> 0.773979902267456 >>> >>> # namedtuple with kwargs >>> >>> Timer('T(a=1, b=2, c=3, d=4, e=5)', setup=''' >>> from collections import namedtuple >>> T = namedtuple("T", "a b c d e")''' >>> ).timeit() >>> 1.155663013458252 >>> >>> ## item access >>> # tuple >>> >>> Timer('t[0], t[1], t[2], t[3], t[4]', setup='t = (1, 2, 3, 4, >>> >>> 5)').timeit() >>> 0.3240630626678467 >>> >>> # namedtuple with indices >>> >>> Timer('t[0], t[1], t[2], t[3], t[4]', setup=''' >>> from collections import namedtuple >>> T = namedtuple("T", "a b c d e") >>> t = T(1, 2, 3, 4, 5)''' >>> ).timeit() >>> 0.2994410991668701 >>> >>> # namedtuple with attributes >>> >>> Timer('t.a, t.b, t.c, t.d, t.e', setup=''' >>> from collections import namedtuple >>> T = namedtuple("T", "a b c d e") >>> t = T(1, 2, 3, 4, 5)''' >>> ).timeit() >>> 0.9363529682159424 >>> >>> It seems that the only significant slowdown is on a namedtuple's >>> creation. I imagine the impact would be negligible on a complete >>> request-response cycle, but that would have to be tested. >>> >>> Accessing a namedtuple's items using attributes is also somewhat slower, >>> but this wouldn't be a problem. Existing code would continue to work with >>> the same performance and users could decide for themselves which way to >>> access a namedtuple's items for new code. >>> >>> On 22 Feb 2014, at 18:37, Florian Apolloner wrote: >>> >>> On Saturday, February 22, 2014 5:24:39 PM UTC+1, Adam Kaliński wrote: >>> >>> What do you guys think? >>> >>> Sounds good, you might check if namedtuple has negative performance >>> effects >>> (I doubt it, but who knows). The reason we didn't add it yet is that it >>> just exists since 2.6. >>> >>> cheers, >>> Florian >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Django developers" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected] <javascript:>. >>> To post to this group, send email to >>> [email protected]<javascript:> >>> . >>> Visit this group at http://groups.google.com/group/django-developers. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/django-developers/61b1a5f0-1d1c-480d-87cd-639c728327a7%40googlegroups.com >>> . >>> For more options, visit https://groups.google.com/groups/opt_out. >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Django developers" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected] <javascript:>. >>> To post to this group, send email to >>> [email protected]<javascript:> >>> . >>> Visit this group at http://groups.google.com/group/django-developers. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/django-developers/699D6AD0-A3F2-425A-805D-8376098707B4%40gmail.com >>> . >>> >>> For more options, visit https://groups.google.com/groups/opt_out. >>> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Django developers" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To post to this group, send email to >> [email protected]<javascript:> >> . >> Visit this group at http://groups.google.com/group/django-developers. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/django-developers/CAJxq84_Q4GgqYN44FJXz9z58Wk%2B_0rvhCrFiz9Tkee4kucko-w%40mail.gmail.com >> . >> >> For more options, visit https://groups.google.com/groups/opt_out. >> > > > > -- > "I disapprove of what you say, but I will defend to the death your right > to say it." -- Evelyn Beatrice Hall (summarizing Voltaire) > "The people's good is the highest law." -- Cicero > GPG Key fingerprint: 125F 5C67 DFE9 4084 > -- You received this message because you are subscribed to the Google Groups "Django developers" group. 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