On 14/08/2019 17:58, Quentin Monnet wrote: > 2019-08-14 17:45 UTC+0100 ~ Edward Cree <ecree@xxxxxxxxxxxxxx> >> This might be a really dumb suggestion, but: you're wanting to collect a >> summary statistic over an in-kernel data structure in a single syscall, >> because making a series of syscalls to examine every entry is slow and >> racy. Isn't that exactly a job for an in-kernel virtual machine, and >> could you not supply an eBPF program which the kernel runs on each entry >> in the map, thus supporting people who want to calculate something else >> (mean, min and max, whatever) instead of count? >> > Hi Edward, I like the approach, thanks for the suggestion. > > But I did not mention that we were using offloaded maps: Tracing the > kernel would probably work for programs running on the host, but this is > not a solution we could extend to hardware offload. I don't see where "tracing" comes into it; this is a new program type and a new map op under the bpf() syscall. Could the user-supplied BPF program not then be passed down to the device for it to run against its offloaded maps?
