On Wed, Apr 2, 2025 at 11:10 AM Ilya Maximets <i.maxim...@ovn.org> wrote:
>
> On 4/2/25 4:47 PM, Mike Pattrick wrote:
> > On Thu, Mar 27, 2025 at 6:11 PM Ilya Maximets <i.maxim...@ovn.org> wrote:
> >>
> >> When the cluster falls apart, there is no leader and so there are no
> >> heartbeats that need to be sent or received on time. In this case
> >> the RAFT_TIMER_THRESHOLD is too small, as the process will only wake
> >> up for a full election timer. When this happens, cooperative
> >> multitasking code will emit warnings and traces thinking there is a
> >> timer overrun.
> >>
> >> Fix that by setting the multitasking interval according to the full
> >> election timer, if there is no known leader.
> >>
> >> Fixes: d4a15647b917 ("ovsdb: raft: Enable cooperative multitasking.")
> >> Signed-off-by: Ilya Maximets <i.maxim...@ovn.org>
> >> ---
> >>
> >> Cc: Frode Nordahl <fnord...@ubuntu.com>
> >>
> >> ovsdb/raft.c | 11 ++++++++---
> >> 1 file changed, 8 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/ovsdb/raft.c b/ovsdb/raft.c
> >> index 9c3c351b5..a9da28780 100644
> >> --- a/ovsdb/raft.c
> >> +++ b/ovsdb/raft.c
> >> @@ -2170,9 +2170,14 @@ raft_run(struct raft *raft)
> >> raft_reset_ping_timer(raft);
> >> }
> >>
> >> - uint64_t interval = raft->joining
> >> - ? RAFT_JOIN_TIMEOUT_MS
> >> - : RAFT_TIMER_THRESHOLD(raft->election_timer);
> >> + uint64_t interval = RAFT_TIMER_THRESHOLD(raft->election_timer);
> >
> > Why not set interval in an else clause?
>
> I had it written this way at first, but then changed for a couple reasons:
>
> 1. The RAFT_TIMER_THRESHOLD is the most common case that we'll use the
> vast majority of the time.
> 2. We'll need to have a negative check for the leader_sid in the else
> branch and the comment in that branch become a little more complicated
> in order to explain what's going on.
>
> 2 may be not a big deal, but 1 seems a good enough reason.
>
> Does that make sense?
Fair enough if this is the stylistic preference.
Acked-by: Mike Pattrick <m...@redhat.com>
> Best regards, Ilya Maximets.
>
> >
> > -M
> >
> >> +
> >> + if (raft->joining) {
> >> + interval = RAFT_JOIN_TIMEOUT_MS;
> >> + } else if (uuid_is_zero(&raft->leader_sid)) {
> >> + /* There are no heartbeats to handle when there is no leader. */
> >> + interval = raft->election_timer;
> >> + }
> >> cooperative_multitasking_set(
> >> &raft_run_cb, (void *) raft, time_msec(),
> >> interval + interval / 10, "raft_run");
> >> --
> >> 2.47.0
> >>
> >> _______________________________________________
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> >> d...@openvswitch.org
> >> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> >>
> >
>
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