Re: [RFC PATCH 00/11] Rust null block driver

[Niklas Cassel]

On Wed, May 03, 2023 at 11:06:57AM +0200, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
> 

(cut)

> 
> For each measurement the drivers are loaded, a drive is configured with memory
> backing and a size of 4 GiB. C null_blk is configured to match the implemented
> modes of the Rust driver: `blocksize` is set to 4 KiB, `completion_nsec` to 0,
> `irqmode` to 0 (IRQ_NONE), `queue_mode` to 2 (MQ), `hw_queue_depth` to 256 and
> `memory_backed` to 1. For both the drivers, the queue scheduler is set to
> `none`. These measurements are made using 30 second runs of `fio` with the
> `PSYNC` IO engine with workers pinned to separate CPU cores. The measurements
> are done inside a virtual machine (qemu/kvm) on an Intel Alder Lake workstation
> (i5-12600).

Hello Andreas,

I'm curious why you used psync ioengine for the benchmarks.

As psync is a sync ioengine, it means queue depth == 1.

Wouldn't it have been more interesting to see an async ioengine,
together with different queue depths?


You might want to explain your table a bit more.
It might be nice to see IOPS and average latencies.

As an example of a table that I find easier to interpret,
see e.g. the table on page 29 in the SPDK performance report:
https://ci.spdk.io/download/performance-reports/SPDK_nvme_bdev_perf_report_2301.pdf


Kind regards,
Niklas