On 2/13/21 9:33 AM, Stokes, Ian wrote: >> On 12/02/2021 17:42, Stokes, Ian wrote: >>>> In order for auto load balance to be enabled, there are >>>> minimum requirements of more than one PMD and more than >>>> one Rxq on at least one PMD. >>>> >>>> If these conditions are not met a rebalance would be pointless, >>>> so auto load balance is not enabled. >>>> >>>> Currently the state is logged but in the case where the criteria >>>> for enabling is not met, there is no reason given. >>>> >>>> It would be useful for the user to see the reason, so they >>>> can understand why auto load balance has not been enabled >>>> when they have requested it. >>>> >>>> For example, if a user has one PMD and sets pmd-auto-lb=true, >>>> previously: >>>> |INFO|PMD auto load balance is disabled >>>> >>>> With patch: >>>> |INFO|PMD auto load balance not enough PMDs or Rx Queues to enable >>>> |INFO|PMD auto load balance is disabled >>> >>> Thanks for the patch Kevin. >>> >>> In testing this worked as expected. >>> >>> One query I had was did you give thought towards more detailed in the log? >>> >> >> I hadn't thought about splitting them. They are both connected as >> increasing the PMDs, will reduce the number of RxQ's per PMD etc. so >> it's hard to be prescriptive in splitting them to tell the user exactly >> what they need to change. >> e.g. >> 2 rxq on 1 pmd "not enough PMDs" >> user increases pmds to 2 >> 1 rxq on 2 pmds "not enough rxqs" >> >> They'd get there in the end, but I wonder if it would be more annoying >> to get a new message after fixing the only one that was reported first >> time around :-) > > I hear ya, not nit picking. Pure spit balling on my side 😃. > >> >>> i.e. if its 1 PMD should we flag that PMD <=1 is an issue. >>> >>> Similar with the number of RXQs. >>> >>> Maybe that's overkill as you could argue the minimum requirements could >> change over time but if its something that could be flagged easily would it >> be >> worth it? >>> >> >> At the moment it's easily added, with the caveat as per above that just >> saying pmds or rxqs alone may not give the full picture. You are right >> that the minimum requirements could change a bit in time, so we could >> end up with further interconnected min reqs which might make it more >> difficult to split. >> > > At the end of the day I suppose we are waiting on users to complain, to date > I haven't those complaints it myself so I assume users are consulting the > documentation and are a ware of the minimum requirements WRT PMD and RXQs. > >> If you think it's useful, I'm fine to add now, or else we can go with a >> single line now and review again later when there is more development on >> it and docs are improved etc. > > I think its better to go with this approach first. We can modify in the > future if required. > > I'd like to see this and patch 1 of the series in OVS 2.15 if there are no > objections. > > @Ilya Maximets any objections to this?
I'm OK with the patch #1, but this one makes me uncomfortable. The main thing that I don't really understand is why we're flipping on/off this feature based on a current rxq distribution at all? The code here wasn't very clear from the start and gets more messy. I'd say that we should, probably, just remove this part and keep load balancing enabled or disabled just based on the user config. Otherwise, we will end up in some overly complicated logic here to print any meaningful log messages. > > If not I can merge. > > BR > Ian >> >>> Thanks >>> Ian >>>> >>>> Signed-off-by: Kevin Traynor <[email protected]> >>>> --- >>>> lib/dpif-netdev.c | 19 +++++++++++++++---- >>>> 1 file changed, 15 insertions(+), 4 deletions(-) >>>> >>>> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c >>>> index 4381c618f..833f45616 100644 >>>> --- a/lib/dpif-netdev.c >>>> +++ b/lib/dpif-netdev.c >>>> @@ -4213,4 +4213,5 @@ set_pmd_auto_lb(struct dp_netdev *dp, bool >>>> always_log) >>>> bool enable_alb = false; >>>> bool multi_rxq = false; >>>> + bool minreq = false; >>>> bool pmd_rxq_assign_cyc = dp->pmd_rxq_assign_cyc; >>>> >>>> @@ -4226,6 +4227,6 @@ set_pmd_auto_lb(struct dp_netdev *dp, bool >>>> always_log) >>>> } >>>> if (cnt && multi_rxq) { >>>> - enable_alb = true; >>>> - break; >>>> + minreq = true; >>>> + break; >>>> } >>>> cnt++; >>>> @@ -4233,6 +4234,5 @@ set_pmd_auto_lb(struct dp_netdev *dp, bool >>>> always_log) >>>> >>>> /* Enable auto LB if it is requested and cycle based assignment is >>>> true. */ >>>> - enable_alb = enable_alb && pmd_rxq_assign_cyc && >>>> - pmd_alb->auto_lb_requested; >>>> + enable_alb = minreq && pmd_rxq_assign_cyc && pmd_alb- >>>>> auto_lb_requested; >>>> >>>> if (pmd_alb->is_enabled != enable_alb || always_log) { >>>> @@ -4251,4 +4251,15 @@ set_pmd_auto_lb(struct dp_netdev *dp, bool >>>> always_log) >>>> } else { >>>> pmd_alb->rebalance_poll_timer = 0; >>>> + if (pmd_alb->auto_lb_requested) { >>>> + if (!minreq) { >>>> + VLOG_INFO("PMD auto load balance not enough " >>>> + "PMDs or Rx Queues to enable"); >>>> + } >>>> + if (!pmd_rxq_assign_cyc) { >>>> + VLOG_INFO("PMD auto load balance needs " >>>> + "'other_config:pmd-rxq-assign=cycles' " >>>> + "to enable"); >>>> + } >>>> + } >>>> VLOG_INFO("PMD auto load balance is disabled"); >>>> } >>>> -- >>>> 2.26.2 >>>> >>>> _______________________________________________ >>>> dev mailing list >>>> [email protected] >>>> https://mail.openvswitch.org/mailman/listinfo/ovs-dev >>> > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
