Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> writes: > On Sun, May 23, 2021 at 4:48 AM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote: >> >> Still wrapping my head around this, but one thing immediately sprang to >> mind: >> >> > + * long bpf_timer_mod(struct bpf_timer *timer, u64 msecs) >> > + * Description >> > + * Set the timer expiration N msecs from the current time. >> > + * Return >> > + * zero >> >> Could we make this use nanoseconds (and wire it up to hrtimers) instead? >> I would like to eventually be able to use this for pacing out network >> packets, and msec precision is way too coarse for that... > > msecs are used to avoid exposing jiffies to bpf prog, since msec_to_jiffies > isn't trivial to do in the bpf prog unlike the kernel. > hrtimer would be great to support as well. > It could be implemented via flags (which are currently zero only) > but probably not as a full replacement for jiffies based timers. > Like array vs hash. bpf_timer can support both. Okay, so this is really: long bpf_timer_mod(struct bpf_timer *timer, u64 interval) where 'interval' will be expressed in either milliseconds or nanoseconds depending on which flags are passed to bpf_timer_init()? That's fine by me, then; I just wanted to make sure that that 'msecs' was not an indication that this was the only granularity these timers would support... :) -Toke
