On Mon, Jun 16, 2025 at 09:41:15AM +0200, Daniel Gomez wrote: > >> Adding support to > >> multiple SGL segments should allow us to increase this limit 256 -> 2048. > >> > >> Is this correct? > > > > Yes. Note that plenty of hardware doesn't really like chained SGLs too > > much and you might get performance degradation. > > > > I see the driver assumes better performance on SGLs over PRPs when I/Os are > greater than 32k (this is the default sgl threshold). Yes. Although that might be worth revisiting - the threshold was we benchmarked on the first hardware we got hold off that supports SGLs. > But what if chaining SGL > is needed, i.e. my host segments are between 4k and 16k, would PRPs perform > better than chaining SGLs? Right now we don't support chaining of SGL descriptors, so that's a moot point. > Also, if host segments are between 4k and 16k, PRPs would be able to support it > but this limit prevents that use case. I guess the question is if you see any > blocker to enable this path? Well, if you think it's worth it give it a spin on a wide variety of hardware.
