[0/3] Add block size histogram qapi interface

Message

zhenwei pi June 20, 2019, 8:54 a.m. UTC

Set/Clear block size histograms through new command
x-block-size-histogram-set and show new statistics in
query-blockstats results.

This command has been tested for half year on QEMU-2.12, and we found
that 3K+ virtual machines write 25GB/s totally, the block size
histogram like following:
        0 ~ 8k: 58% ~ 62%
        8k ~ 32k: 10% ~ 12%
        32k ~ 128k: 2% ~ 3%
        128K ~ 512K: 24% ~ 26%
        512K ~ : ...

And the histogram data help us to optimise backend distributed
storage.

zhenwei pi (3):
  block/accounting: rename struct BlockLatencyHistogram
  block/accounting: introduce block size histogram
  qapi: add block size histogram interface

 block/accounting.c         |  55 ++++++++++++++++++------
 block/qapi.c               |  26 ++++++++++-
 blockdev.c                 |  56 ++++++++++++++++++++++++
 include/block/accounting.h |  12 ++++--
 qapi/block-core.json       | 105 ++++++++++++++++++++++++++++++++++++++++++++-
 5 files changed, 235 insertions(+), 19 deletions(-)