Documentation/ABI/rnbd-clt: Add description for nr_poll_queues

describe how to set nr_poll_queues and enable the polling

Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-15-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Gioh Kim 2021-04-19 09:37:17 +02:00 committed by Jens Axboe
parent 2958a995ed
commit 015fcf13c4
2 changed files with 19 additions and 0 deletions

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@ -56,3 +56,9 @@ Date: Feb 2020
KernelVersion: 5.7
Contact: Jack Wang <jinpu.wang@cloud.ionos.com> Danil Kipnis <danil.kipnis@cloud.ionos.com>
Description: Remap the disconnected device if the session is not destroyed yet.
What: /sys/block/rnbd<N>/rnbd/nr_poll_queues
Date: Feb 2020
KernelVersion: 5.7
Contact: Jack Wang <jinpu.wang@cloud.ionos.com> Danil Kipnis <danil.kipnis@cloud.ionos.com>
Description: Contains the number of poll-mode queues

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@ -85,6 +85,19 @@ Description: Expected format is the following::
By default "rw" is used.
nr_poll_queues
specifies the number of poll-mode queues. If the IO has HIPRI flag,
the block-layer will send the IO via the poll-mode queue.
For fast network and device the polling is faster than interrupt-base
IO handling because it saves time for context switching, switching to
another process, handling the interrupt and switching back to the
issuing process.
Set -1 if you want to set it as the number of CPUs
By default rnbd client creates only irq-mode queues.
NOTICE: MUST make a unique session for a device using the poll-mode queues.
Exit Codes:
If the device is already mapped it will fail with EEXIST. If the input