large, disposable files?
large, disposable files?
- Subject: large, disposable files?
- From: Andrew Gallatin <email@hidden>
- Date: Tue, 13 Mar 2007 09:40:18 -0400 (EDT)
I'm dealing with applications which read large (many GB, much larger
than physical memory) files at a moderate rate of speed (a few
MB/sec). They generally make one pass through the file and delete it.
There is no benefit at all to caching the file in the kernel. The
caching which is done is extremely detrimental as it causes all kinds
of unnecessary paging; the OS pages out other applications which
happen to be idle at the time in favor of caching the files which will
never be read again.
I doesn't look like Darwin/MacOSX has an O_DIRECT option to disable
caching on the file at open time. Does MacOSX/Darwin have a way to
disabling caching on a per-mountpoint basis?
Failing that, the last Mach based OS I used (DEC OSF/1) had all kinds
of nice tuning parameters to prevent the unified buffer cache from
taking over too much physical memory. See, for example, the
description of ubc-maxpercent at
http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/HTML/AA-Q0R3E-TET1_html/tune2.html#ubc
Is there some sort of option like ubc-maxpercent in Darwin/MacOSX that
I'm not seeing?
Thanks,
Drew
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Darwin-kernel mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden