From: Felipe Balbi > Bin Liu <binmlist@xxxxxxxxx> writes: > > [ text/plain ] > > Hi, > > > > On Fri, Mar 11, 2016 at 6:54 AM, Felipe Balbi > > <felipe.balbi@xxxxxxxxxxxxxxx> wrote: > >> previously we were using a maximum of 32 TRBs per > >> endpoint. With each TRB being 16 bytes long, we were > >> using 512 bytes of memory for each endpoint. > >> > >> However, SLAB/SLUB will always allocate PAGE_SIZE > >> chunks. In order to better utilize the memory we > >> allocate and to allow deeper queues for gadgets > >> which would benefit from it (g_ether comes to mind), > >> let's increase the maximum to 256 TRBs which rounds > >> up to 4096 bytes for each endpoint. > > > > Do we want to increase the same for event ring buffers as > > while, which is allocated by dma_alloc_coherent(), which > > is also at PAGE_SIZE chunks, right? > > I could, but that's much less important. Currently we have up to 2 > events per endpoint which is very, very unlikely to happen. Plus, in > that case there's no tangible benefit. $subject, however, I've been > using on some performance optimization I've been trying to achieve (not > ready for submission just yet). Is it worth considering using a single mapped page for the small rings of multiple devices? David -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
