Date: Mon, 16 Jul 2007 05:06:57 -0700 From: Garrett Cooper <youshi10@u.washington.edu> To: hackers@freebsd.org Subject: Large gap between fwrite and write, and fread and read Message-ID: <469B5F61.1060805@u.washington.edu>
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Hello again Hackers,
I ran some tests and I noticed a large difference in the cumulative
sums of fwrite(2) vs write(3) and fread(2) vs read(3) (3-fold
differences on a real machine).
Please download
<http://students.washington.edu/youshi10/posted/fat.tgz>, take a look at
README for some results, and read for more details on how you can run
the tests as well if curious, and feel free to send me the results if
desired. If you do run the tests, please don't use the /tmp disk at all
on the machine as it will most likely skew parts of the test, and please
pay heed to the warning, otherwise the test box may become unusable.
One thing that has me puzzled though... why is there such a large
difference? Is it because fread(2) allows object by object instantiation
(i.e. preallocates objects according to sizeof and returns the number of
allocated figures), whereas read(3) just reads in raw lengths and
returns the amount of chars scanned in? Does the same logic apply for
fwrite(2) and write(3)?
Thanks,
-Garrett -- I really need to go to bed earlier.. haha.
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