lock files shared between library and scripts #336
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Well, I gave this a shot and unfortunately, the extra lock/unlock calls don't seem to help on one system where I can reproduce the problem. Bummer! This may still help on some NFS file systems, though adding the lock/unlock calls could presumably slow things down a bit. Sigh. |
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There are a number of files shared between the library and the run scripts, including
flush.scr,halt.scr,nodes.scr,index.scrand the summary and rank2file maps among others. While in most cases, the library is not trying to access those files the same time as the scripts, this PR adds read/write locks around shared files to help avoid NFS caching problems.If the library updates the flush file from a compute node and then stops, and then the job script reads the flush file from another node, it may see a stale copy due to NFS caching. The hope is that adding read/write locks will help mitigate those caching problems on some NFS implementations.