Messages in this thread | | | Date | Fri, 28 Jun 2013 11:58:28 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 0/8] perf: add ability to sample physical data addresses |
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On Wed, Jun 26, 2013 at 09:10:50PM +0200, Stephane Eranian wrote: > After more investigation with the author of the false sharing > detection tool, I think > that if the mapping changes, it is okay. The tool can detect this and > drop the analysis > at that address. So as long as we can flag the mapping change, we are > okay. Hopefully, > it does not occur frequently. If so, then I think there are bigger > issues to fix on the system > than false sharing.
But if you index everything using dev:inode:offset it doesn't matter if the mapping changes; you're invariant to map placement.
And the thing is; we already compute most of that anyway in order to find the code in DSOs, except there we use filename instead of dev:inode. However if there were means to open files using dev:inode that might actually be more reliable than using the filename.
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