http://ayende.comAyende @ RahienCopyright (C) Ayende Rahien 2004 - 2021 (c) 202660Definitely QOTD, and quite fitting, given the emails that I've just been handling today. http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment9http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment9Fri, 08 Jan 2010 14:38:01 GMT"Nothing helps if you are stupid" -- love it; my QOTD! http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment8http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment8Mon, 28 Dec 2009 16:31:04 GMTI have to do a lot of text processing. Can you think of anything better suited than regexes to do that? From both performance and maintainability points of view? http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment7http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment7Sat, 26 Dec 2009 06:40:13 GMTHave you tought about _not_ using Regexes at all? http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment6http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment6Sat, 26 Dec 2009 00:25:00 GMTFirefly, The problem is that you only get ~15 LRU cache. That doesn't work for something like the profiler, who does a LOT of regexes http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment5http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment5Fri, 25 Dec 2009 20:14:17 GMTMS actually recommend to use the static methods on Regex in most cased since it'll be cached automatically. I've always found it more intuitive to do the caching myself hence turn it into a static field. http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment4http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment4Fri, 25 Dec 2009 15:16:17 GMTCreating a new Regex object with the compiled option does cause it to be compiled over and over, destroying performance. I've been caught out by it myself. The solution is to either reuse the same object or use one of the static methods on Regex, which do look up to see whether a compiled instance of the regex already exists. http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment3http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment3Fri, 25 Dec 2009 11:26:21 GMTstill odd though, as creating a regex will always pull a cached instance into itself which does the actual work. You have a little bit of overhead from looking up the instance and the key construction (check the ctor) but it's not recompiled over and over again. So that it has drastic performance improvements is a little unexpected. http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment2http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment2Fri, 25 Dec 2009 10:39:52 GMTFunny bug. It seems this object was polluting address space of application while being compiled again and again into new assembly and hooking up till app ends. http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment1http://ayende.com/4338/uberprof-performance-improvements-nothing-helps-if-you-are-stupid#comment1Fri, 25 Dec 2009 10:35:11 GMT