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  1. Lustre
  2. LU-19574

Increasing the size of oh_buckets in obd_histogram

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    • Improvement
    • Resolution: Unresolved
    • Medium
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    • 3
    • 9223372036854775807

    Description

      Right now, the bucket size is 32 and anything greater than it will be fell into the last bucket. It has been used widely in the Lustre code base, in particular the number of pending IO to disk is using this. This might be good enough for the HDD era but nowdays NVME SSD can support many more pending IOs. For example, it's not uncommon to see a NVME SSD device to support 10+ queue pairs with 1K queue size for each queue. 

      This has caused issue to a recent performance investigation. I would propose to have a log2 based histogram.

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          is related to

          Bug - A problem which impairs or prevents the functions of the product. LU-4533 rpc_stats histogram does not support max_rpcs_in_flight greater than 31

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Open

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              Jinshan Jinshan Xiong
              jinshanx Jinshan Xiong
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                Created:
                Updated: