| Message ID | 1556786363-28743-5-git-send-email-magnus.karlsson@intel.com |
|---|---|
| State | RFC |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | busy poll support for AF_XDP sockets | expand |
On 5/2/2019 1:39 AM, Magnus Karlsson wrote: > This patch introduces a new setsockopt that enables busy-poll for XDP > sockets. It is called XDP_BUSY_POLL_BATCH_SIZE and takes batch size as > an argument. A value between 1 and NAPI_WEIGHT (64) will turn it on, 0 > will turn it off and any other value will return an error. There is > also a corresponding getsockopt implementation. I think this socket option should also allow specifying a timeout value when using blocking poll() calls. OR can we use SO_BUSY_POLL to specify this timeout value? > > Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> > --- > include/uapi/linux/if_xdp.h | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h > index caed8b1..be28a78 100644 > --- a/include/uapi/linux/if_xdp.h > +++ b/include/uapi/linux/if_xdp.h > @@ -46,6 +46,7 @@ struct xdp_mmap_offsets { > #define XDP_UMEM_FILL_RING 5 > #define XDP_UMEM_COMPLETION_RING 6 > #define XDP_STATISTICS 7 > +#define XDP_BUSY_POLL_BATCH_SIZE 8 > > struct xdp_umem_reg { > __u64 addr; /* Start of packet data area */ >
On Fri, May 3, 2019 at 2:26 AM Samudrala, Sridhar <sridhar.samudrala@intel.com> wrote: > > > > On 5/2/2019 1:39 AM, Magnus Karlsson wrote: > > This patch introduces a new setsockopt that enables busy-poll for XDP > > sockets. It is called XDP_BUSY_POLL_BATCH_SIZE and takes batch size as > > an argument. A value between 1 and NAPI_WEIGHT (64) will turn it on, 0 > > will turn it off and any other value will return an error. There is > > also a corresponding getsockopt implementation. > > I think this socket option should also allow specifying a timeout value > when using blocking poll() calls. > OR can we use SO_BUSY_POLL to specify this timeout value? I think you are correct in that we need to be able to specify the timeout. The current approach of always having a timeout of zero was optimized for the high throughput case. But Ilias and others often talk about using AF_XDP for time sensitive networking, and in that case spinning in the kernel (for a max period of the timeout) waiting for a packet would provide better latency. And with a configurable value, we could support both cases, so why not. I will add the timeout value to the new setsockopt I introduced, so it will take both a batch size and a timeout value. I will also call it something else since it should not have batch_size in its name anymore. Thanks: Magnus > > > > Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> > > --- > > include/uapi/linux/if_xdp.h | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h > > index caed8b1..be28a78 100644 > > --- a/include/uapi/linux/if_xdp.h > > +++ b/include/uapi/linux/if_xdp.h > > @@ -46,6 +46,7 @@ struct xdp_mmap_offsets { > > #define XDP_UMEM_FILL_RING 5 > > #define XDP_UMEM_COMPLETION_RING 6 > > #define XDP_STATISTICS 7 > > +#define XDP_BUSY_POLL_BATCH_SIZE 8 > > > > struct xdp_umem_reg { > > __u64 addr; /* Start of packet data area */ > >
diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h index caed8b1..be28a78 100644 --- a/include/uapi/linux/if_xdp.h +++ b/include/uapi/linux/if_xdp.h @@ -46,6 +46,7 @@ struct xdp_mmap_offsets { #define XDP_UMEM_FILL_RING 5 #define XDP_UMEM_COMPLETION_RING 6 #define XDP_STATISTICS 7 +#define XDP_BUSY_POLL_BATCH_SIZE 8 struct xdp_umem_reg { __u64 addr; /* Start of packet data area */
This patch introduces a new setsockopt that enables busy-poll for XDP sockets. It is called XDP_BUSY_POLL_BATCH_SIZE and takes batch size as an argument. A value between 1 and NAPI_WEIGHT (64) will turn it on, 0 will turn it off and any other value will return an error. There is also a corresponding getsockopt implementation. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> --- include/uapi/linux/if_xdp.h | 1 + 1 file changed, 1 insertion(+)