Subject: Re: Proposed new syscalls: pread and pwrite
To: None <firstname.lastname@example.org>
From: Stefan Grefen <email@example.com>
Date: 12/05/1995 05:41:41
In message <199512042101.NAA26144@cygnus.com> "J.T. Conklin" wrote:
> My officemate Stu was reading the Solaris manual last Friday and
> noticed the syscalls pread() and pwrite(). Those calls are like
> read() and write() but also take an offset argument like lseek().
> He mentioned that TOPS-20 had something similar, and it resulted
> in a 10-15% performance improvement on database like applications.
What you see is the systemcall overhead for the lseek. Make syscalls
faster and the benefit becomes smaller and smaller ...
> Although the type of applications that benefit from this new syscall
> is small, I think the performance improvement warrants the inclusion
> of these new syscalls in NetBSD. Even such things as mundane as DB
> would seem to benefit from the new functionality.
Every program would benefit from faster syscalls ...
I'm working for a company building 'scalable' system. Most time the
scalabilty is limited by poorly designed/implemented basic functions.
That's why I'm stressing the 'basics' here.
(For SLOWARIS compatibility the syscall is of course needed and on a
multi-cpu system it's mandatory or atomic seek/writes become a very
complicated and slow function).
Stefan Grefen Convex Computer GmbH, Frankfurt, Germany
firstname.lastname@example.org Phone: +49-69-665270
fortune: "You can't make a program without broken egos."