X-Authentication-Warning: delorie.com: mail set sender to djgpp-bounces using -f From: Charles Sandmann Newsgroups: comp.os.msdos.djgpp Subject: Re: HELP with DPMI under DOS - Part II Date: Tue, 21 Oct 2003 09:14:19 CDT Organization: Rice University, Houston, TX Lines: 35 Message-ID: <3f953833.sandmann@clio.rice.edu> References: <3f944c94 DOT sandmann AT clio DOT rice DOT edu> <8N6lb.684$947 DOT 530 AT nntpserver DOT swip DOT net> NNTP-Posting-Host: clio.rice.edu X-Trace: joe.rice.edu 1066745980 7318 128.42.105.3 (21 Oct 2003 14:19:40 GMT) X-Complaints-To: abuse AT rice DOT edu NNTP-Posting-Date: Tue, 21 Oct 2003 14:19:40 +0000 (UTC) X-NewsEditor: ED-1.5.9 To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Reply-To: djgpp AT delorie DOT com > 5) for Charlies Sandman: I will try to use sbrk(), I use to disable swap > file I will turn it on again (what about performance?). When using over 500MB of memory with cwsdpmi r5, the page tables will fault and cause slower performance. If you have a disk cache, or put a 2MB swap file on a ram disk you can lower the performance hit. But the fix for this is to use the current "test" release of cwsdpmi r6: http://clio.rice.edu/djgpp/csdpmi6t.zip I haven't messed with it in almost 2 years (not a lot of requests for more than 500MB of memory under DOS). Eventually I planned to support 4GB, but I don't have a system with more than 2GB for testing right now. I am considering making some major memory management changes for the final release which would limit the 4KB page space to the first 256MB and use 4MB pages for anything over that. But trying to document that behavior, which would violate the DPMI specification, is a mess. > Some question where I will find cwsdpmi r6 and pmode/dj ? http://clio.rice.edu/djgpp/pmode13b.zip is the most current pmode. > What about the unreal mode with djgpp executable ? Not an option. Pmode is the best option for a minimal overhead DPMI provider, especially if you don't need paging. You might need to remove HIMEM to work properly in some cases. > If I use sbrk() I will have performance lost? No, malloc() calls sbrk(), so you will actually potentially gain performance. You won't give up extra memory to store the malloc data structures.