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Quick Lists
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Bug ID:
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6822204
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Votes
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0
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Synopsis
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volatile fences should prefer lock:addl to actual mfence instructions
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Category
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hotspot:compiler2
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Reported Against
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Release Fixed
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hs15(b05),
7(b54) (Bug ID:2175676)
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State
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10-Fix Delivered,
bug
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Priority:
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3-Medium
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Related Bugs
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Submit Date
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25-MAR-2009
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Description
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When generating code for volatile memory accesses on x86 we currently use the mfence instruction if it is available and fall back to a lock:addl [esp], 0 when it's not. For the purposes of volatile synchronization they are equivalent in power but on some processors the mfence is more expensive so we should prefer the lock:addl idiom.
Posted Date : 2009-03-25 20:08:20.0
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Work Around
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N/A
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Evaluation
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The fix is to put the logic for using lock:addl into membar and use membar in the appropriate places. mfence should always generate mfence.
Posted Date : 2009-03-25 20:09:30.0
http://hg.openjdk.java.net/jdk7/hotspot-comp/hotspot/rev/d0994e5bebce
Posted Date : 2009-03-27 00:07:51.0
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Comments
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PLEASE NOTE: JDK6 is formerly known as Project Mustang
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