3 ms·

Does anyone know whether these optimisations in block layer and iouring benefit major IO hitters like PostgreSQL, ZFS, NFS writes etc? Will it take several year

Does anyone know whether these optimisations in block layer and iouring benefit major IO hitters like PostgreSQL, ZFS, NFS writes etc? Will it take several years and monumental effort before they adopt iouring first?

wtallis 5y ago
io_uring is an improved interface between userspace and the kernel, so it doesn't provide any direct benefits to in-kernel filesystem operations, and the performance benefits io_uring does provide should be largely filesystem-agnostic. That said, some of these recent optimizations may be low enough in the kernel's io stack to also benefit io originating within the kernel itself. Userspace applications that already have some support for asynchronous disk IO (either through the old libaio APIs or as a cleanly-abstracted thread pool) should be able to switch to using io_uring as their backend without too much trouble, and reap the benefits of async that actually works reliably (if switching from libaio) and with vastly lower overhead (if switching from a thread pool). Databases like PostgreSQL were some of the few applications that attempted to deal with the limitations of libaio, but I'm not sure how close they are to having a production-quality io_uring backend.
- sumtechguy 5y ago
  From an earlier article https://www.phoronix.com/scan.php?page=news_item&px=Linux-Approaching-7M-IOPS https://www.phoronix.com/scan.php?page=news_item&px=Linux-Ap... "His patches pushing the greater performance have been changes to the block code, NVMe, multi-queue blk-mq, and IO_uring." https://git.kernel.dk/cgit/linux-block/log/?h=perf-wip https://git.kernel.dk/cgit/linux-block/log/?h=perf-wip So it looks like he is playing with a good portion of the IO block stack with a very recent concentration on io_uring. So maybe some of it?...

3 ms·

Does anyone know whether these optimisations in block layer and iouring benefit major IO hitters like PostgreSQL, ZFS, NFS writes etc? Will it take several year

by reacharavindh 5y ago

wtallis 5y ago
io_uring is an improved interface between userspace and the kernel, so it doesn't provide any direct benefits to in-kernel filesystem operations, and the performance benefits io_uring does provide should be largely filesystem-agnostic. That said, some of these recent optimizations may be low enough in the kernel's io stack to also benefit io originating within the kernel itself. Userspace applications that already have some support for asynchronous disk IO (either through the old libaio APIs or as a cleanly-abstracted thread pool) should be able to switch to using io_uring as their backend without too much trouble, and reap the benefits of async that actually works reliably (if switching from libaio) and with vastly lower overhead (if switching from a thread pool). Databases like PostgreSQL were some of the few applications that attempted to deal with the limitations of libaio, but I'm not sure how close they are to having a production-quality io_uring backend.
- sumtechguy 5y ago
  From an earlier article https://www.phoronix.com/scan.php?page=news_item&px=Linux-Approaching-7M-IOPS https://www.phoronix.com/scan.php?page=news_item&px=Linux-Ap... "His patches pushing the greater performance have been changes to the block code, NVMe, multi-queue blk-mq, and IO_uring." https://git.kernel.dk/cgit/linux-block/log/?h=perf-wip https://git.kernel.dk/cgit/linux-block/log/?h=perf-wip So it looks like he is playing with a good portion of the IO block stack with a very recent concentration on io_uring. So maybe some of it?...