Re: FUSE: [Regression] Fuse legacy path performance scaling lost in v6.14 vs v6.8/6.11 (iodepth scaling with io_uring)

[Bernd Schubert <bernd@bsbernd.com>]

Hi Abhishek,

On 11/27/25 14:37, Abhishek Gupta wrote:
> Hi Bernd,
> 
> Thanks for looking into this.
> Please find below the fio output on 6.11 & 6.14 kernel versions.
> 
> 
> On kernel 6.11
> 
> ~/gcsfuse$ uname -a
> Linux abhishek-c4-192-west4a 6.11.0-1016-gcp #16~24.04.1-Ubuntu SMP
> Wed May 28 02:40:52 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
> 
> iodepth = 1
> :~/fio-fio-3.38$ ./fio --name=randread --rw=randread
> --ioengine=io_uring --thread
> --filename_format='/home/abhishekmgupta_google_com/bucket/$jobnum'
> --filesize=1G --time_based=1 --runtime=15s --bs=4K --numjobs=1
> --iodepth=1 --group_reporting=1 --direct=1
> randread: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
> 4096B-4096B, ioengine=io_uring, iodepth=1
> fio-3.38
> Starting 1 thread
> ...
> Run status group 0 (all jobs):
>    READ: bw=3311KiB/s (3391kB/s), 3311KiB/s-3311KiB/s
> (3391kB/s-3391kB/s), io=48.5MiB (50.9MB), run=15001-15001msec
> 
> iodepth=4
> :~/fio-fio-3.38$ ./fio --name=randread --rw=randread
> --ioengine=io_uring --thread
> --filename_format='/home/abhishekmgupta_google_com/bucket/$jobnum'
> --filesize=1G --time_based=1 --runtime=15s --bs=4K --numjobs=1
> --iodepth=4 --group_reporting=1 --direct=1
> randread: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
> 4096B-4096B, ioengine=io_uring, iodepth=4
> fio-3.38
> Starting 1 thread
> ...
> Run status group 0 (all jobs):
>    READ: bw=11.0MiB/s (11.6MB/s), 11.0MiB/s-11.0MiB/s
> (11.6MB/s-11.6MB/s), io=166MiB (174MB), run=15002-15002msec
> 
> 
> On kernel 6.14
> 
> :~$ uname -a
> Linux abhishek-west4a-2504 6.14.0-1019-gcp #20-Ubuntu SMP Wed Oct 15
> 00:41:12 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
> 
> iodepth=1
> :~$ fio --name=randread --rw=randread --ioengine=io_uring --thread
> --filename_format='/home/abhishekmgupta_google_com/bucket/$jobnum'
> --filesize=1G --time_based=1 --runtime=15s --bs=4K --numjobs=1
> --iodepth=1 --group_reporting=1 --direct=1
> randread: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
> 4096B-4096B, ioengine=io_uring, iodepth=1
> fio-3.38
> Starting 1 thread
> ...
> Run status group 0 (all jobs):
>    READ: bw=3576KiB/s (3662kB/s), 3576KiB/s-3576KiB/s
> (3662kB/s-3662kB/s), io=52.4MiB (54.9MB), run=15001-15001msec
> 
> iodepth=4
> :~$ fio --name=randread --rw=randread --ioengine=io_uring --thread
> --filename_format='/home/abhishekmgupta_google_com/bucket/$jobnum'
> --filesize=1G --time_based=1 --runtime=15s --bs=4K --numjobs=1
> --iodepth=4 --group_reporting=1 --direct=1
> randread: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
> 4096B-4096B, ioengine=io_uring, iodepth=4
> fio-3.38
> ...
> Run status group 0 (all jobs):
>    READ: bw=3863KiB/s (3956kB/s), 3863KiB/s-3863KiB/s
> (3956kB/s-3956kB/s), io=56.6MiB (59.3MB), run=15001-15001msec

assuming I would find some time over the weekend and with the fact that
I don't know anything about google cloud, how can I reproduce this?


Thanks,
Bernd