Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
| From | jgk@panix.com (Joe keane) |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: a = b or memset/cpy? |
| Date | 2012-02-08 20:05 +0000 |
| Organization | Public Access Networks Corp. |
| Message-ID | <jgukhf$199$1@reader1.panix.com> (permalink) |
| References | <abb85a15-f68c-4e2f-8985-fe8b4945aca0@t8g2000yqg.googlegroups.com> |
In article <abb85a15-f68c-4e2f-8985-fe8b4945aca0@t8g2000yqg.googlegroups.com>, nroberts <roberts.noah@gmail.com> wrote: >memset and memcpy are turning up in profiles a lot. Indeed. >Sometimes it is clear that using = to initialize a local would be >better than memset. It's a shame if you call a function with a size parameter, when in fact the size is a compile-time constant. You also probably know a bit about alignment, whereas those guys have to assume the worst. >I might not gain anything, but at least there's a chance. Please to use real data! 'gprof' is very good at this. It works [so far as i have seen] on stdlib calls as well as your functions. It can tell you where you're getting killed by function call overhead, and where the copy is taking a long time, such that you may go to more length to avoid it. It can also (by switching back to a function) tell you where your 'optimization' does nothing except increase code size.
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
a = b or memset/cpy? nroberts <roberts.noah@gmail.com> - 2012-02-07 09:02 -0800
Re: a = b or memset/cpy? Jens Gustedt <jens.gustedt@loria.fr> - 2012-02-07 18:41 +0100
Re: a = b or memset/cpy? James Kuyper <jameskuyper@verizon.net> - 2012-02-07 13:40 -0500
Re: a = b or memset/cpy? Jens Gustedt <jens.gustedt@loria.fr> - 2012-02-07 20:09 +0100
Re: a = b or memset/cpy? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-07 11:37 -0800
Re: a = b or memset/cpy? Shao Miller <sha0.miller@gmail.com> - 2012-02-07 18:35 -0500
Re: a = b or memset/cpy? nroberts <roberts.noah@gmail.com> - 2012-02-07 11:07 -0800
Re: a = b or memset/cpy? blp@cs.stanford.edu (Ben Pfaff) - 2012-02-07 11:14 -0800
Re: a = b or memset/cpy? nroberts <roberts.noah@gmail.com> - 2012-02-07 11:41 -0800
Re: a = b or memset/cpy? Shao Miller <sha0.miller@gmail.com> - 2012-02-07 18:39 -0500
Re: a = b or memset/cpy? "Scott Fluhrer" <sfluhrer@ix.netcom.com> - 2012-02-07 14:14 -0500
Re: a = b or memset/cpy? Shao Miller <sha0.miller@gmail.com> - 2012-02-07 18:58 -0500
Re: a = b or memset/cpy? Shao Miller <sha0.miller@gmail.com> - 2012-02-07 21:58 -0500
Re: a = b or memset/cpy? Jens Gustedt <jens.gustedt@loria.fr> - 2012-02-09 21:34 +0100
Re: a = b or memset/cpy? Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-02-07 20:34 -0500
Re: a = b or memset/cpy? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-02-08 18:43 +0000
Re: a = b or memset/cpy? jgk@panix.com (Joe keane) - 2012-02-08 20:05 +0000
Re: a = b or memset/cpy? Ian Collins <ian-news@hotmail.com> - 2012-02-09 09:18 +1300
Re: a = b or memset/cpy? Tim Prince <tim@nospamcomputer.org> - 2012-02-14 08:30 -0500
csiph-web