[Qemu-block] [PATCH v2 0/3] Add block size histogram qapi interface

[zhenwei pi]

Modify command 'block-latency-histogram-set' to make block histogram
interface common to use. And support block size histogram.
Thanks to Eric Blake&Vladimir Sementsov-Ogievskiy for the suggestions.

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.

Changelog:
v2:
  - make 'block-latency-histogram-set' common.
  - remove duplicated functions.
  - fix uncommon indentation(reviewed by Vladimir Sementsov-Ogievskiy).

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

 block/accounting.c         |  62 ++++++++++++++++++++--------
 block/qapi.c               |  32 ++++++++------
 blockdev.c                 |  33 +++++++++++----
 include/block/accounting.h |  13 +++---
 qapi/block-core.json       | 101 +++++++++++++++++++++++++++------------------
 5 files changed, 158 insertions(+), 83 deletions(-)

-- 
2.11.0