Hi all,
there had been several attempts to implement a latency-based I/O
scheduler for native nvme multipath, all of which had its issues.
So time to start afresh, this time using the QoS framework
already present in the block layer.
It consists of two parts:
- a new 'blk-nodelat' QoS module, which is just a simple per-node
latency tracker
- a 'latency' nvme I/O policy
Using the 'tiobench' fio script I'm getting:
WRITE: bw=531MiB/s (556MB/s), 33.2MiB/s-52.4MiB/s
(34.8MB/s-54.9MB/s), io=4096MiB (4295MB), run=4888-7718msec
WRITE: bw=539MiB/s (566MB/s), 33.7MiB/s-50.9MiB/s
(35.3MB/s-53.3MB/s), io=4096MiB (4295MB), run=5033-7594msec
READ: bw=898MiB/s (942MB/s), 56.1MiB/s-75.4MiB/s
(58.9MB/s-79.0MB/s), io=4096MiB (4295MB), run=3397-4560msec
READ: bw=1023MiB/s (1072MB/s), 63.9MiB/s-75.1MiB/s
(67.0MB/s-78.8MB/s), io=4096MiB (4295MB), run=3408-4005msec
for 'round-robin' and
WRITE: bw=574MiB/s (601MB/s), 35.8MiB/s-45.5MiB/s
(37.6MB/s-47.7MB/s), io=4096MiB (4295MB), run=5629-7142msec
WRITE: bw=639MiB/s (670MB/s), 39.9MiB/s-47.5MiB/s
(41.9MB/s-49.8MB/s), io=4096MiB (4295MB), run=5388-6408msec
READ: bw=1024MiB/s (1074MB/s), 64.0MiB/s-73.7MiB/s
(67.1MB/s-77.2MB/s), io=4096MiB (4295MB), run=3475-4000msec
READ: bw=1013MiB/s (1063MB/s), 63.3MiB/s-72.6MiB/s
(66.4MB/s-76.2MB/s), io=4096MiB (4295MB), run=3524-4042msec
for 'latency' with 'decay' set to 10.
That's on a 32G FC testbed running against a brd target,
fio running with 16 thread.
As usual, comments and reviews are welcome.
Hannes Reinecke (2):
block: track per-node I/O latency
nvme: add 'latency' iopolicy
block/Kconfig | 7 +
block/Makefile | 1 +
block/blk-mq-debugfs.c | 2 +
block/blk-nodelat.c | 368 ++++++++++++++++++++++++++++++++++
block/blk-rq-qos.h | 6 +
drivers/nvme/host/multipath.c | 46 ++++-
drivers/nvme/host/nvme.h | 2 +
include/linux/blk-mq.h | 11 +
8 files changed, 439 insertions(+), 4 deletions(-)
create mode 100644 block/blk-nodelat.c
--
2.35.3
