| Message ID | 20241003233850.199495-1-jdamato@fastly.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | igc: Link IRQs and queues to NAPIs | expand |
Joe Damato <jdamato@fastly.com> writes: > Greetings: > > This is an RFC to get feedback before submitting an actual series and > because I have a question for igc maintainers, see below. > > This series addss support for netdev-genl to igc so that userland apps > can query IRQ, queue, and NAPI instance relationships. This is useful > because developers who have igc NICs (for example, in their Intel NUCs) > who are working on epoll-based busy polling apps and using > SO_INCOMING_NAPI_ID, need access to this API to map NAPI IDs back to > queues. > > See the commit messages of each patch for example output I got on my igc > hardware. > > My question for maintainers: > > In patch 2, the linking should be avoided for XDP queues. Is there a way > to test that somehow in the driver? I looked around a bit, but didn't > notice anything. Sorry if I'm missing something obvious. > From a quick look, it seems that you could "unlink" the XDP queues in igc_xdp_enable_pool() and (re-)link them in igc_xdp_disable_poll(). Or just the existence of the flag IGC_RING_FLAG_AF_XDP_ZC in the rings associated with the queue is enough? I still have to take a better look at your work to help more, sorry. > Thanks, > Joe > > Joe Damato (2): > igc: Link IRQs to NAPI instances > igc: Link queues to NAPI instances > > drivers/net/ethernet/intel/igc/igc.h | 1 + > drivers/net/ethernet/intel/igc/igc_main.c | 33 ++++++++++++++++++++--- > 2 files changed, 30 insertions(+), 4 deletions(-) > > -- > 2.25.1 > > Cheers,
On Mon, Oct 07, 2024 at 04:03:00PM -0700, Vinicius Costa Gomes wrote: > Joe Damato <jdamato@fastly.com> writes: > > > Greetings: > > > > This is an RFC to get feedback before submitting an actual series and > > because I have a question for igc maintainers, see below. > > > > This series addss support for netdev-genl to igc so that userland apps > > can query IRQ, queue, and NAPI instance relationships. This is useful > > because developers who have igc NICs (for example, in their Intel NUCs) > > who are working on epoll-based busy polling apps and using > > SO_INCOMING_NAPI_ID, need access to this API to map NAPI IDs back to > > queues. > > > > See the commit messages of each patch for example output I got on my igc > > hardware. > > > > My question for maintainers: > > > > In patch 2, the linking should be avoided for XDP queues. Is there a way > > to test that somehow in the driver? I looked around a bit, but didn't > > notice anything. Sorry if I'm missing something obvious. > > > > From a quick look, it seems that you could "unlink" the XDP queues in > igc_xdp_enable_pool() and (re-)link them in igc_xdp_disable_poll(). That approach seems reasonable to me, but I am not an igc expert by any means :) I checked and it seems that igc_xdp_enable_pool and igc_xdp_disable_poll are only called while RTNL is held, which is good because netif_queue_set_napi uses ASSERT_RTNL. > Or just the existence of the flag IGC_RING_FLAG_AF_XDP_ZC in the rings > associated with the queue is enough? I didn't notice that flag, thanks for pointing that out. It might be better to go the link/unlink route as you described above, though. > I still have to take a better look at your work to help more, sorry. No worries, thanks for taking a look. I'll implement what you suggested above and send another RFC.