Commit 891bf99a authored by Piotr Pelplinski's avatar Piotr Pelplinski Committed by Jim Harris
Browse files

histograms: add doc for bdev histograms 



Signed-off-by: default avatarPiotr Pelplinski <piotr.pelplinski@intel.com>
Change-Id: Ie042df61e6fbae583cffb5022d3e26ca078f67fb

Reviewed-on: https://review.gerrithub.io/c/442558


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarTomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
parent 67c3074b

doc/bdev.md

+21 −0
Original line number Diff line number Diff line
@@ -81,6 +81,27 @@ specified. When both rate limits are enabled, the first met limit will 
take effect.  The value 0 may be specified to disable the corresponding rate

limit. Users can run this command with `-h` or `--help` for more information.



## Histograms {#rpc_bdev_histogram}



The `enable_bdev_histogram` RPC command allows to enable or disable gathering

latency data for specified bdev. Histogram can be downloaded by the user by

calling `get_bdev_histogram` and parsed using scripts/histogram.py script.



Example command



`rpc.py enable_bdev_histogram Nvme0n1 --enable`



The command will enable gathering data for histogram on Nvme0n1 device.



`rpc.py get_bdev_histogram Nvme0n1 | histogram.py`



The command will download gathered histogram data. The script will parse

the data and show table containing IO count for latency ranges.



`rpc.py enable_bdev_histogram Nvme0n1 --disable`



The command will disable histogram on Nvme0n1 device.



## delete_bdev {#bdev_ug_delete_bdev}



To remove previously created bdev user can use `delete_bdev` RPC command.