On Sun, Nov 07, 1999 at 10:44:43PM +0100, Martin Mares wrote:
> Hello, world!\n
>
> I'm currently writting my own database library (a much faster alternative
> to GDBM) and I want to sort file accesses before feeding them to the kernel,
> so that they will be executed in linear sector order and seek time will be
> minimized. Unfortunately, this plan breaks on the FIBMAP ioctl requiring
> CAP_SYS_RAWIO capability. To be honest, I don't see why -- can the kernel
> gurus advise me what deep reasons are behind this restriction?
Hmpf, I played with the idea to keep track of the seek pointer in
userland by writing a wrapper-library between an app and glibc.
The library replaces "lseek/write" combinations by pwrite and
the same for writev(,,1). It's a totally different idea but
great to reduce the number of syscalls.
http://homepage.sime.com/stefan/software/libcacheglibcwrapper.c
It is part of a full autoconf/automake/libtool distribution for
that but it would need a cleanup (at least one person here knows why...).
Contact me to force a cleanup, it's hard to get it up without config.h ;-}
but you should see the (cool ?) idea behind it.
It keeps the linux-specific optimizing stuff out of your source.
--ciao - Stefan
"you have moved your mouse, please reboot to make this change take effect"
Stefan Traby phone: +43-3133-6107-2 Mitterlasznitzstr. 13 fax: +43-3133-6107-9 8302 Nestelbach mailto://stefan@sime.com Austria http://homepage.sime.com/stefan
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