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Groups > comp.lang.c++ > #13639
| From | Ian Collins <ian-news@hotmail.com> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: Oozing poison |
| Date | 2012-01-29 11:59 +1300 |
| Message-ID | <9ojcuqF8j0U15@mid.individual.net> (permalink) |
| References | (9 earlier) <qGKUq.152389$624.85025@news.usenetserver.com> <87d3a44es0.fsf@catnip.gol.com> <ROZUq.97141$ka3.2190@news.usenetserver.com> <9ojbcpF8j0U13@mid.individual.net> <15745250.325.1327791325896.JavaMail.geo-discussion-forums@prhs5> |
On 01/29/12 11:55 AM, 88888 Dihedral wrote: > 在 2012年1月29日星期日UTC+8上午6时32分57秒，Ian Collins写道： >> On 01/29/12 10:31 AM, Scott Lurndal wrote: >>> Miles Bader<mi...@gnu.org> writes: >>>> scott@slp53.sl.home (Scott Lurndal) writes: >>>>>> The catch is also the reason for all the extra code, constructing and >>>>>> destructing a temporary std::exception object. The actual exception >>>>>> handling part of the code is this bit: >>>>> >>>>> Yet creating and destroying a temporary std::exception object also counts in >>>>> terms of both extra cycles and code footprint. Both of which impact >>>>> performance (generally negatively). >>>> >>>> Er, exceptions are intended to be _exceptional_. >>>> >>>> If some exception occurs so often that it has a measurable performance >>>> impact, it probably shouldn't be an exception. >>> >>> The exception never occurs (i.e., I never run out of memory). It's the >>> added code to handle the exception and it's effect on a (very) hot codepath >>> that causes the 4% hit in performance. That is the only change in the >>> codebase, and I ran the benchmark three times with each flavor (try/catch/new >>> vs. malloc). I have to admit that I was surprised by the difference and I'm >>> going to take a look at the actual codepaths and do some profiling to see why >>> adding a try/catch clause has such a large effect, when the exception is never >>> taken. >> >> How about new (without the exceptions) compared to malloc? new is doing >> more work than malloc, one reason I suggested a specialised allocator. > > Well, an object with some methods to generate new objects not to be garbage collected very soon following the o stack push-pop mechnism of auto varibles are somewaht evil in C++ if the programmer does not think carefully and write codes to chain these methods in class B arbitrarily then there might be a definitely expoenti ally growth rate of the heap used by a lousy fat programming hog in some programs. Do what? -- Ian Collins
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Oozing poison AD <isquat@gmail.com> - 2012-01-10 04:35 -0800
Re: Oozing poison Leigh Johnston <leigh@i42.co.uk> - 2012-01-10 15:19 +0000
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-11 00:43 -0800
Re: Oozing poison "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-01-11 10:01 +0100
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-11 22:09 +1300
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-11 01:42 -0800
Re: Oozing poison Leigh Johnston <leigh@i42.co.uk> - 2012-01-11 13:36 +0000
Re: Oozing poison John Bokma <john@castleamber.com> - 2012-01-11 10:08 -0600
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-12 06:08 -0800
Re: Oozing poison Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 14:13 +0000
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-17 02:08 -0800
Re: Oozing poison Henrik Faber <hfaber@invalid.net> - 2012-01-17 12:50 +0100
Re: Oozing poison Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-13 02:18 -0800
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-17 02:24 -0800
Re: Oozing poison Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-11 16:50 +0000
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-12 06:04 -0800
Re: Oozing poison Victor Bazarov <v.bazarov@comcast.invalid> - 2012-01-12 10:13 -0500
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-17 02:19 -0800
Re: Oozing poison Victor Bazarov <v.bazarov@comcast.invalid> - 2012-01-17 08:04 -0500
Re: Oozing poison Miles Bader <miles@gnu.org> - 2012-01-18 13:51 +0900
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-21 04:40 -0800
Re: Oozing poison Quint Rankid <qbr567@gmail.com> - 2012-01-21 09:05 -0800
Re: Oozing poison Wil Evers <bouncer@dev.null> - 2012-01-21 18:52 +0000
Re: Oozing poison Quint Rankid <qbr567@gmail.com> - 2012-01-21 11:33 -0800
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-25 02:23 -0800
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-25 02:07 -0800
Re: Oozing poison Victor Bazarov <v.bazarov@comcast.invalid> - 2012-01-25 07:59 -0500
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-26 07:54 +1300
Re: Oozing poison Pavel <pauldontspamtolk@removeyourself.dontspam.yahoo> - 2012-01-21 22:43 -0500
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-22 21:05 +1300
Re: Oozing poison Pavel <pauldontspamtolk@removeyourself.dontspam.yahoo> - 2012-01-22 18:21 -0500
Re: Oozing poison Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-23 15:55 +0000
Re: Oozing poison gwowen <gwowen@gmail.com> - 2012-01-23 08:37 -0800
Re: Oozing poison Pavel <pauldontspamtolk@removeyourself.dontspam.yahoo> - 2012-01-24 22:48 -0500
Re: Oozing poison Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-25 19:44 +0000
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-26 08:56 +1300
Re: Oozing poison 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-25 23:04 -0800
Re: Oozing poison Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-26 03:24 -0800
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-26 19:13 +0000
Re: Oozing poison Brian Drummond <brian@shapes.demon.co.uk> - 2012-01-27 00:12 +0000
Re: Oozing poison "MikeWhy" <boat042-nospam@yahoo.com> - 2012-01-26 22:44 -0600
Re: Oozing poison 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-28 14:25 -0800
Re: Oozing poison Robert Miles <milesrf@Usenet-News.net> - 2012-02-26 22:16 -0600
Re: Oozing poison "Gernot Frisch" <me@privacy.net> - 2012-01-24 18:21 +0100
Re: Oozing poison Victor Bazarov <v.bazarov@comcast.invalid> - 2012-01-24 12:41 -0500
Re: Oozing poison Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-26 03:25 -0800
Re: Oozing poison Rui Maciel <rui.maciel@gmail.com> - 2012-01-25 19:44 +0000
Re: Oozing poison Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-26 09:44 +0000
Re: Oozing poison Rui Maciel <rui.maciel@gmail.com> - 2012-01-26 10:36 +0000
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-26 19:18 +0000
Re: Oozing poison Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-26 20:42 +0000
Re: Oozing poison Juha Nieminen <nospam@thanks.invalid> - 2012-01-26 16:30 +0000
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-26 19:24 +0000
Re: Oozing poison Cholo Lennon <chololennon@hotmail.com> - 2012-01-26 17:13 -0300
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-26 20:55 +0000
Re: Oozing poison Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-26 22:08 +0000
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-27 00:32 +0000
Re: Oozing poison Dombo <dombo@disposable.invalid> - 2012-01-28 12:59 +0100
Re: Oozing poison Cholo Lennon <chololennon@hotmail.com> - 2012-01-27 18:28 -0300
Re: Oozing poison Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-29 18:02 +0000
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-27 20:18 +1300
Re: Oozing poison Miles Bader <miles@gnu.org> - 2012-01-27 18:09 +0900
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-27 20:29 +0000
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-28 10:06 +1300
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-27 21:26 +0000
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-28 12:22 +1300
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-28 04:18 +0000
Re: Oozing poison Miles Bader <miles@gnu.org> - 2012-01-28 13:44 +0900
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-28 21:31 +0000
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-29 11:32 +1300
Re: Oozing poison 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-28 14:55 -0800
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-29 11:59 +1300
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-30 17:08 +0000
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-28 18:06 +1300
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-28 22:49 +0000
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-29 12:22 +1300
Re: Oozing poison scott@slp53.sl.home (Scott Lurndal) - 2012-01-27 20:16 +0000
Re: Oozing poison Ian Collins <ian-news@hotmail.com> - 2012-01-28 10:01 +1300
Re: Oozing poison Juha Nieminen <nospam@thanks.invalid> - 2012-01-28 16:00 +0000
Re: Oozing poison Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-10 21:42 +0000
Re: Oozing poison AD <isquat@gmail.com> - 2012-01-17 02:31 -0800
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