Mercurial > hg > blitz_condensed
view src/org/dancres/blitz/config/Fifo.java @ 34:6f68e94c1fb8 default tip
Add CondensedStats monitoring utility, equivalent to vmstat
author | Dominic Cleal <dominic-cleal@cdo2.com> |
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date | Thu, 05 Aug 2010 11:07:25 +0100 |
parents | 3dc0c5604566 |
children |
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package org.dancres.blitz.config; /** <p>Fifo constraint causes searching of Entry's to be done in approximately oldest first order.</p> <p>FIFO ordering is, essentially, cache defeating in that it demands loading the <em>least</em> recently used Entry's rather than favouring <em>most recently</em> used Entry's. Therefore, enabling FIFO will reduce overall performance of Blitz which may be countered by assumptions you can make in your JavaSpaces code</p> <p>Note that FIFO is <em>not</em> a requirement of the JavaSpaces spec and you cannot assume all JavaSpaces implementations provide FIFO support. Thus, by using the Blitz FIFO facility, you are potentially locking yourself in.</p> <p>Note that the number of pending dirty writes can significantly affect FIFO performance. Normally, one configures Blitz with a large pending writes buffer to reduce IO and increase performance. When FIFO is enabled, large write buffers introduce significant amounts of additional processing thus you are advised to reduce the size of <code>desiredPendingWrites</code> to of the order of <code>100</code>.</p> */ public class Fifo implements EntryConstraint { private static final String TYPE = "FIFO"; public Fifo() { } public int hashCode() { return TYPE.hashCode(); } public boolean equals(Object anObject) { return (anObject instanceof Fifo); } }