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| From | Ian Collins <ian-news@hotmail.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: position in file when saving |
| Date | 2016-03-31 16:19 +1300 |
| Message-ID | <dm3jalF92p2U1@mid.individual.net> (permalink) |
| References | (18 earlier) <nddu6i$sbk$1@jstuckle.eternal-september.org> <dm033rFr730U1@mid.individual.net> <ndemh3$ujq$1@jstuckle.eternal-september.org> <dm05ebFr730U2@mid.individual.net> <ndhg5t$fse$1@jstuckle.eternal-september.org> |
On 03/31/16 10:27, Jerry Stuckle wrote: > > Here's the results of a quick program I wrote to compute a CRC32 on all > .h, .c and .o files in a directory structure. The test is checking > every source file for all architectures in the Linux source. > >>> time ./crctest /usr/src/linux-source-4.2.0/linux-source-4.2.0 > 38933 files computed, total byte count 534546283 > > real 1m52.269s > user 0m0.472s > sys 0m8.836s > > However, this was in a 2GB virtual machine (Oracle VM VirtualBox) > running an Ubuntu guest under Windows 7 on a notebook with a relatively > slow hard disk. The "disk" is actually an 8GB file on Windows, which > makes disk access even slower. But it's a good test environment when > you aren't overly worried about performance. > > When I rerun the test, all of the files will be in buffers and the > results are much different: > >>> time ./crctest /usr/src/linux-source-4.2.0/linux-source-4.2.0 > 38933 files computed, total byte count 534546283 > > real 0m3.485s > user 0m2.380s > sys 0m1.020s > > About 3.5 seconds total to checksum 39K files and 500+Mb. > > I would say that's not very time consuming. I would expect that running > on a desktop with a reasonably fast disk would show pretty good performance. 150MB/sec for reading small files is *very* good performance. Imagine how fast it would be if it only had to check modification times. > And these tests are much more accurate than yours. That I doubt. -- Ian Collins
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position in file when saving fir <profesor.fir@gmail.com> - 2016-03-24 08:29 -0700
Re: position in file when saving Barry Schwarz <schwarzb@dqel.com> - 2016-03-24 10:11 -0700
Re: position in file when saving fir <profesor.fir@gmail.com> - 2016-03-24 10:51 -0700
Re: position in file when saving Robert Wessel <robertwessel2@yahoo.com> - 2016-03-24 13:07 -0500
Re: position in file when saving Stephen Sprunk <stephen@sprunk.org> - 2016-03-24 14:22 -0500
Re: position in file when saving supercat@casperkitty.com - 2016-03-24 12:40 -0700
Re: position in file when saving Keith Thompson <kst-u@mib.org> - 2016-03-24 12:57 -0700
Re: position in file when saving supercat@casperkitty.com - 2016-03-24 13:15 -0700
Re: position in file when saving Keith Thompson <kst-u@mib.org> - 2016-03-24 15:06 -0700
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-24 20:29 -0400
Re: position in file when saving Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-03-25 01:42 +0000
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-24 23:07 -0400
Re: position in file when saving Ian Collins <ian-news@hotmail.com> - 2016-03-25 16:21 +1300
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-25 09:00 -0400
Re: position in file when saving Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-03-25 11:07 +0000
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-25 09:06 -0400
Re: position in file when saving Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-03-25 14:22 +0000
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-25 10:57 -0400
Re: position in file when saving Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-03-25 16:31 +0000
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-25 12:36 -0400
Re: position in file when saving luser droog <luser.droog@gmail.com> - 2016-03-25 09:49 -0700
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-25 13:00 -0400
Re: position in file when saving Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-03-25 20:35 +0000
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-25 16:59 -0400
Re: position in file when saving Ian Collins <ian-news@hotmail.com> - 2016-03-26 10:46 +1300
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-25 20:22 -0400
Re: position in file when saving Ian Collins <ian-news@hotmail.com> - 2016-03-26 13:42 +1300
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-26 09:17 -0400
Re: position in file when saving supercat@casperkitty.com - 2016-03-26 07:50 -0700
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-26 21:37 -0400
Re: position in file when saving supercat@casperkitty.com - 2016-03-27 08:14 -0700
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-27 12:45 -0400
Re: position in file when saving supercat@casperkitty.com - 2016-03-27 12:20 -0700
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-27 17:07 -0400
Re: position in file when saving supercat@casperkitty.com - 2016-03-27 14:15 -0700
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-27 17:26 -0400
Re: position in file when saving Ken Brody <kenbrody@spamcop.net> - 2016-03-28 10:36 -0400
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-28 11:01 -0400
Re: position in file when saving David Brown <david.brown@hesbynett.no> - 2016-03-29 10:18 +0200
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-29 09:02 -0400
Re: position in file when saving Ian Collins <ian-news@hotmail.com> - 2016-03-30 08:24 +1300
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-29 15:57 -0400
Re: position in file when saving Ian Collins <ian-news@hotmail.com> - 2016-03-30 09:04 +1300
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-29 16:22 -0400
Re: position in file when saving Ian Collins <ian-news@hotmail.com> - 2016-03-31 17:31 +1300
Re: position in file when saving gazelle@shell.xmission.com (Kenny McCormack) - 2016-03-31 09:55 +0000
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-31 10:01 -0400
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-29 16:31 -0400
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-30 17:27 -0400
Re: position in file when saving Ian Collins <ian-news@hotmail.com> - 2016-03-31 16:19 +1300
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-31 10:06 -0400
Re: position in file when saving Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-03-29 05:21 -0700
Re: position in file when saving Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-29 09:05 -0400
Re: position in file when saving Ken Brody <kenbrody@spamcop.net> - 2016-03-25 14:33 -0400
Re: position in file when saving Keith Thompson <kst-u@mib.org> - 2016-03-25 11:38 -0700
Re: position in file when saving supercat@casperkitty.com - 2016-03-25 14:05 -0700
Re: position in file when saving Nick Bowler <nbowler@draconx.ca> - 2016-03-28 16:14 +0000
Re: position in file when saving Tim Rentsch <txr@alumni.caltech.edu> - 2016-03-30 09:31 -0700
Re: position in file when saving Ian Collins <ian-news@hotmail.com> - 2016-03-25 15:06 +1300
Re: position in file when saving Ian Collins <ian-news@hotmail.com> - 2016-03-25 15:00 +1300
Re: position in file when saving Les Cargill <lcargill99@comcast.com> - 2016-03-24 22:15 -0500
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