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- Path: sparky!uunet!zaphod.mps.ohio-state.edu!cs.utexas.edu!news
- From: wilson@cs.utexas.edu (Paul Wilson)
- Newsgroups: comp.sys.dec
- Subject: block and fetch size for ULTRIX on DECstation 5000/200
- Date: 29 Jul 1992 10:30:53 -0500
- Organization: CS Dept, University of Texas at Austin
- Lines: 22
- Message-ID: <l7deddINNt72@boogie.cs.utexas.edu>
- NNTP-Posting-Host: boogie.cs.utexas.edu
- Summary: why is file system faster than VM?
-
- I'm getting some unexpectedly good performance numbers with some
- software I'm running, which looks like it's because file system
- block reads are faster than virtual memory pageins.
-
- Can anybody tell me offhand what's going on? I'm reading 4K
- blocks from files, and it's unexpectedly fast. My guess is
- that the filesystem is actually fetching 8K blocks, where the
- VM system is fetching 4K pages, or maybe the file system is
- doing one-block lookahead prefetching.
-
- We're using ULTRIX 4.1.
-
- Any clarification would be appreciated.
-
- Thanks,
-
- Paul
- --
- | Paul R. Wilson wilson@cs.utexas.edu |
- | U. of Texas Computer Sciences Dept. voice: (512) 471-9555 |
- | Taylor Hall 2.124, Austin, TX 78712-1188 fax: (512) 471-8885 |
- | "Inertia makes the world go 'round." |
-