05-14-2009
Quote:
Originally Posted by
emitrax
I just stumbled across linux syscall readahead().
Do you think it can be used to improve performances even further ?
Or is it just an alternative way of setvbuf ?
Thanks again.
I don't know Linux but I Google'd the readahead call and it seems to be the system equivalent of the mmap call. Only difference seems to be that while mmap loads the file contents into the user process readahead does the same thing but puts it all into the system buffer cache in units of pagesize.
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LEARN ABOUT HPUX
readahead
readahead(8) System Manager's Manual readahead(8)
NAME
readahead - file preloader for boot process optimization
SYNOPSIS
readahead [options] <file-list> [another-file-list [...]]
DESCRIPTION
readahead is a files preloader designed to optimize the disk I/O during the boot process.
OPTIONS
-b, --build
build optimised files list only, without sorting.
-s, --sort
build and sort list of files only (implies -b).
-o, --output <file>
write sorted list of files to file.
-d, --dont-sort
preload files described by an already sorted files list.
-h, --help
print the usage information.
-v, --verbose
enable the verbose mode.
-t, --timing
report time spent on each operation.
-m, --maxsize <max size>
maximum size in KiB a file can be in order to be preloaded, default is 10240.
<file-list> [another-file-list [...]]
One or more files containing the list of files to be preloaded or sorted. The files list can be generated by readahead-collector(8).
FILES
/etc/default/readahead-fedora
SEE ALSO
readahead-collector(8), readahead(2),
AUTHORS
Arjan van de Ven <arjan@infradead.org>,
Ziga Mahkovec <ziga.mahkovec@klika.si>, Karel Zak <kzak@redhat.com>,
This manual page was written by Raphael Geissert <geissert@debian.org>
July 2011 readahead(8)