stefanha

Can you explain what the examples are showcasing? I looked at the Audio and Webserver examples. They give the LF syntax for doing something that is easier to do directly in Python. I'm missing the advantages of LF and why you'd want to do this in the first place.

Have you checked out Pianoteq? It is physical modeling and sounds incredible. It even runs on a RaspberryPi of you want.

When it comes to real instruments, Roland ships physical modeling in some of their instruments. They are a mainstream company.

So I think physical modeling is there but harder to get right than recording samples of piano keys being pressed. The results can be been convincing and it's nice that it requires little memory compared to sample based techniques.

It's not. In the demo video the exploit code is a Linux kernel module, not a userspace application.

9P is a filesystem protocol (like NFS or CIFS) rather than a local file system (like btrfs or NTFS). It's used to share files between the host and the guest. That way there's no need to copy files between the host and the guest.

virt-builder is an alternative to installing a guest OS from scratch. It has a selection of popular guest OSes template images that you can quickly install non-interactively.

It's convenient when you don't want to manually install a guest and also don't want to figure out preseed/kickstart/etc.

It makes creating new KVM guests easier and has handy features like the ability to copy in ssh keys so you can connect to the guest right away.

> The full build of all Git functionality in Rust is currently around 27M, but since a large part of it is a library, it could clearly be easily split up into domains of functionality - subcrates that do specific things.

I downloaded v0.3.99 for Linux x86_64 and stripped the binary. It ends up at 31 MB. The .text section is 25 MB.

I'm surprised by the large size. On my system /usr/bin/git is 4.7 MB, although git is split up into multiple programs. I'm not comparing apples to apples, but this is weird.

If anyone digs into the binary size, please share what you find.

In Linux (Wayland) you can copy text from the terminal without pressing Ctrl+C at all. Just select the text. To paste it in another Window, press the middle mouse button.

This is called the Primary Selection and is separate from the Clipboard (Ctrl+C/Ctrl+V). IMO the Primary Selection is more convenient than the Clipboard.

@graveland Which Linux interface was used for the userspace block driver (ublk, nbd, tcmu-runner, NVMe-over-TCP, etc)? Why did you choose it?

Also, were existing network or distributed file systems not suitable? This use case sounds like Ceph might fit, for example.

qemu-img convert supports copy_file_range(2) too. Was the `--copy-range-offloading` option used in the benchmark?

It would be helpful to share the command-line and details of how benchmarks were run.

I'm the presenter of the talk, but not an io_uring kernel developer or security expert.

The io_uring implementation is complex and the number of lines of code is non-trivial. On the other hand, as code matures and the number of bugs being reported falls, the trade-off between functionality gained and risk of security issues changes. More people will decide to use io_uring as time passes. People already rely on much larger and more complex subsystems like the network stack or file systems.

It looks plausible: XFS's xfs_dio_write_end_io() updates the on-disk file size. Do you have a link to documentation that confirms this is true for Linux or POSIX filesystems?

Edit: POSIX 1003.1-2017 defines fdatasync(2) behavior in 3.384 Synchronized I/O Data Integrity Completion, where it says "For write, when the operation has been completed or diagnosed if unsuccessful. The write is complete only when the data specified in the write request is successfully transferred and all file system information required to retrieve the data is successfully transferred".

So I think POSIX does guarantee that a write at the end of the file with O_DSYNC/followed by fdatasync(2) (and therefore, Linux RWF_DSYNC) is sufficient. Thank you for pointing out that RWF_DSYNC is sufficient for appends, vlovich123!

io_uring is available from RHEL 9.3 onward. The catch is that it's disabled by default and needs to be enabled at runtime via the "kernel.io_uring_disabled" sysctl.

Agreed, when metadata changes are involved then RWF_SYNC must be used.

RWF_DSYNC is sufficient and faster when data is overwritten without metadata changes to the file.