BRT: Skip duplicate BRT prefetches #15941
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If there is a pending entry for this block, then we've already issued BRT prefetch for it within this TXG, so don't do it again. BRT vdev lookup and following zap_prefetch_uint64() call can be pretty expensive and should be avoided when not necessary. Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc.
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pjd
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If there is a pending entry for this block, then we've already issued BRT prefetch for it within this TXG, so don't do it again. BRT vdev lookup and following zap_prefetch_uint64() call can be pretty expensive and should be avoided when not necessary. Reviewed-by: Pawel Jakub Dawidek <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15941
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If there is a pending entry for this block, then we've already issued BRT prefetch for it within this TXG, so don't do it again. BRT vdev lookup and following zap_prefetch_uint64() call can be pretty expensive and should be avoided when not necessary. Reviewed-by: Pawel Jakub Dawidek <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes #15941
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If there is a pending entry for this block, then we've already issued BRT prefetch for it within this TXG, so don't do it again. BRT vdev lookup and following zap_prefetch_uint64() call can be pretty expensive and should be avoided when not necessary. Reviewed-by: Pawel Jakub Dawidek <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15941
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If there is a pending entry for this block, then we've already issued BRT prefetch for it within this TXG, so don't do it again. BRT vdev lookup and following zap_prefetch_uint64() call can be pretty expensive and should be avoided when not necessary.
How Has This Been Tested?
Created 10GB file and cloned it several times consecutively. Profiler show large CPU time reduction for the cp thread.
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Signed-off-by.