From 891bf99aaa42bf63ee860ffcbcc9c6307dfd59c0 Mon Sep 17 00:00:00 2001 From: Piotr Pelplinski Date: Tue, 29 Jan 2019 13:52:21 +0100 Subject: [PATCH] histograms: add doc for bdev histograms Signed-off-by: Piotr Pelplinski Change-Id: Ie042df61e6fbae583cffb5022d3e26ca078f67fb Reviewed-on: https://review.gerrithub.io/c/442558 Tested-by: SPDK CI Jenkins Reviewed-by: Tomasz Zawadzki Reviewed-by: Ben Walker Reviewed-by: Jim Harris --- doc/bdev.md | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/doc/bdev.md b/doc/bdev.md index e0ef49096..2cc6104f1 100644 --- a/doc/bdev.md +++ b/doc/bdev.md @@ -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.