Article View: comp.arch
Article #12838caches and the kernel
From: Phil Ngai
Date: Sun, 18 Jan 1987 06:25
Date: Sun, 18 Jan 1987 06:25
21 lines
1577 bytes
1577 bytes
Several people have told me that although it is hard to simulate (one
person suggested using a logic analyzer to get address traces), it
does seem to be the case that the Unix kernel does not interact with
caches as well as applications such as nroff. This led me to wonder if
in that case, one might not do well to turn off the cache while the
processor is in supervisor mode, since the hit rate does not seem to
be very high and you thereby avoid flushing the cache of information
that is useful to the application. This assumes the kernel was entered
through a system call and returned to the same process. If a new
process was run, then 1) the cache would probably have to be much
larger and 2) process switches probably happen at a rate low enough
that it doesn't matter if the cache is invalidated. Anyway, these are
just guesses and I would like to invite discussion on this subject.
--
Warning: the California AAA is pursuing a policy which would spend
gasoline taxes on mass transit instead of roads.
Phil Ngai +1 408 749 5720
UUCP: {ucbvax,decwrl,hplabs,allegra}!amdcad!phil
ARPA: amdcad!phil@decwrl.dec.com
Technical Details
Message-ID:
<14362@amdcad.UUCP>Path:
arc1-ca.pugleaf.net!utzoo!mnetor!seismo!rutgers!ames!amdahl!amdcad!philShow Full Headers
Complete Article Headers
Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!mnetor!seismo!rutgers!ames!amdahl!amdcad!phil From: phil@amdcad.UUCP (Phil Ngai) Newsgroups: comp.arch Subject: caches and the kernel Message-ID: <14362@amdcad.UUCP> Date: Sun, 18-Jan-87 01:25:39 EST Article-I.D.: amdcad.14362 Posted: Sun Jan 18 01:25:39 1987 Date-Received: Sun, 18-Jan-87 07:40:29 EST Organization: AMDCAD, Sunnyvale, CA Lines: 21