Re: [RFC PATCH v3 0/3] introduce io_uring_cmd_import_fixed_vec

[Sidong Yang]

On Mon, Mar 17, 2025 at 10:32:02AM +0000, Mark Harmstone wrote:
> On 16/3/25 07:22, Pavel Begunkov wrote:
> > > 
> > On 3/15/25 17:23, Sidong Yang wrote:
> >> This patche series introduce io_uring_cmd_import_vec. With this function,
> >> Multiple fixed buffer could be used in uring cmd. It's vectored version
> >> for io_uring_cmd_import_fixed(). Also this patch series includes a usage
> >> for new api for encoded read/write in btrfs by using uring cmd.
> >>
> >> There was approximately 10 percent of performance improvements through 
> >> benchmark.
> >> The benchmark code is in
> >> https://github.com/SidongYang/btrfs-encoded-io-test/blob/main/main.c
> >> ./main -l
> >> Elapsed time: 0.598997 seconds
> >> ./main -l -f
> >> Elapsed time: 0.540332 seconds
> > 
> > It's probably precise, but it's usually hard to judge about
> > performance from such short runs. Mark, do we have some benchmark
> > for the io_uring cmd?
> 
> Unfortunately not. My plan was to plug it in to btrfs-receive and to use 
> that as a benchmark, but it turned out that the limiting factor there 
> was the dentry locking.
> 
> Sidong, Pavel is right - your figures would be more useful if you ran it 
> 1,000 times or so.

Yes, it would be useful for large number of repetitions.

Thanks,
Sidong

> 
> Mark