On 5/26/26 6:42 AM, Theodore Tso wrote:

It seems... surprising that the additional I/O operations are actually
throttloing UFS device bandwidth by 2x (4GB/s vs 2GB/s).  Have you dug
into why this is happening, and whether there is anything that can be
optimized below the file system?

The layers below the filesystem (block, SCSI, UFS) is what I'm
responsible for in the Pixel team and I can assure you that these are
highly optimized.

Since the transfer size used in Jaegeuk's tests is much larger than 4
KiB, how many CPU cycles are used per IO by the layers below the
filesystem is not limiting the transfer bandwidth.

Bart.