On UNIX, I can, for example, tell the OS that the mapping will be needed in the future with posix_fadvise(POSIX_FADV_WILLNEED). It will then read-ahead the data if it feels so.
How to tell the access intend to Windows ?
views:
293answers:
3
+1
A:
You can pass FILE_FLAG_RANDOM_ACCESS or FILE_FLAG_SEQUENTIAL_SCAN to CreateFile()
Anders
2009-07-29 16:58:44
Are that the only hinting possibilities on Windows ?
Steve Schnepp
2009-07-30 06:46:57
As far as hints go, I think so. You can disable caching and things like that, but some of those other flags have alignment requirements so its more than a simple hint
Anders
2009-07-30 09:57:28
A:
Actually, as Anders mostly suggested, there is no such method in the memory management functions.
2 different ways exists to do something similar :
- Read the data asynchronously with ReadFileEx. The data might then still be in the file cache when needed later.
- Open the file with a streaming hint with the
FILE_FLAG_SEQUENTIAL_SCANattribute of CreateFile. Readahead would then perhaps be automatically done.
Steve Schnepp
2009-12-08 17:19:16
A:
Steve/Anders, that may be fine when you are reading files, but what about memory mapped regions? I can't see any equivalent to madvise(, , MADV_WILLNEED) ...
Michael Fuller
2009-12-10 23:27:50
As I said, it seems that only workarounds exist : *no such method in the mm functions*.
Steve Schnepp
2009-12-11 07:59:45