Re: [PATCH] Portable dumper fixes for NT
On Sat, 15 Jan 2000, Kirill Katsnelson <kkm(a)dtmx.com> wrote:
Some time ago, Hrvoje Niksic wrote...
>"Kirill 'Big K' Katsnelson" <kkm(a)dtmx.com> writes:
[...]
A question: does mmap gives any performance benefits over read when
loading the dump file? NT is primarily a single-user system, so the
case of 2+ xemacsen should be rare, and the shared memory benefit
would not pay off.
Vaguely. Win2K ships with terminal services as a default or, if not
that, a very easy addition. I also know a number of large companies that
are looking at using that sort of thing internally (including ours).
WinNT has finally completed the transition to implement Unix. Multiple
user WinNT machines and a network-distributed GUI layer are there...
So, on that basis, I think that the mapping advantage should not be
discounted if the cost of it is low.
I will fake mmap if it gives performance benefits though, even a
little. Startup seems to be slower a bit.
Win32 provides mmap natively, even if libc does not expose it. The
interface is low level but is detailed by Microsoft:
<URL:http://msdn.microsoft.com/library/psdk/winbase/filemap_0583.htm>
Daniel
--
The youth gets together his materials to build a bridge to the moon, or,
perchance, a palace or temple on the earth, and, at length, the middle-aged
man concludes to build a woodshed with them.
-- Henry David Thoreau