Hi, Looking at the code again I think it looks promising a further enhancement could Be to add a flags field indicating the search method if the value_string is "full" E.g. all values 0-x used the value could be directly used as an index to the sought string.
I just need to find the time to do some profiling/tests... Regards Anders -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Jakub Zawadzki Sent: den 22 april 2010 23:40 To: Ed Beroset; Developer support list for Wireshark Subject: Re: [Wireshark-dev] RFC: sorted value_string + bsearch On Thu, Apr 22, 2010 at 10:47:14AM -0400, Ed Beroset wrote: > I may have missed it, but have we measured to see if this is worth optimizing > in the first place? I have some old callgrind log, where match_strval (for 58736 frames) is called a lot: from dissect_ieee80211 58,7k from ieee_80211_add_tagged_parameters 228k It's problem with ieee80211 dissector, but when you grep dissector sources: #v+ $ grep -Ir 'val_to_str' ./ | wc -l 3621 $ grep -Ir 'match_strval' ./ | wc -l 305 #v- It's a common thing to use these functions. > If not, I think I'd favor choosing code Come on, this code require only adding: static const VALUE_STRING_FAST(some_value_string_array); I don't see much difference between using: value_to_str_fast(..., &foo_fast) and value_to_str(..., foo) If you don't like automatic variable naming I can replace VALUE_STRING_FAST with: #define VALUE_STRING_FAST_INIT(x) = { array_length(x)-1, x } static const value_string_fast foo = VALUE_STRING_FAST_INIT(bar); Dissector maintainer is free to use old/new (or write his own) function he want, but putting 57 new lines to core won't hurt. > clarity over an inconsequential speedup. ATM I don't have working profiler to benchmark wireshark, but I made some _raw_ benchmark [1], for 5k entries and searching 0 to 6k three times Average time for 16 tests: val_to_str_fast: 0.02s val_to_str: 1.56s Sorry for not providing real-life benchmark. Cheers. [1] http://szara.chmurka.net/value_string-bench.c ___________________________________________________________________________ Sent via: Wireshark-dev mailing list <[email protected]> Archives: http://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev mailto:[email protected]?subject=unsubscribe ___________________________________________________________________________ Sent via: Wireshark-dev mailing list <[email protected]> Archives: http://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev mailto:[email protected]?subject=unsubscribe
