Hi,
On 01/18/2018 05:44 AM, Jamal Hadi Salim wrote: > One more comment: > Probably try to run a test with a very small delta with > no offload (probably using something like prio as the root qdisc) > and dump the stats. > My gut feeling is your accounting of the backlog in particular is off. You were right, thanks. It'll be fixed on our next version. Regards, Jesus > > cheers, > jamal > > On 18-01-18 08:35 AM, Jamal Hadi Salim wrote: >> On 18-01-17 06:06 PM, Jesus Sanchez-Palencia wrote: >>> From: Vinicius Costa Gomes <vinicius.go...@intel.com> >>> >>> TBS (Time Based Scheduler) uses the information added earlier in this >>> series (the socket option SO_TXTIME and the new role of >>> sk_buff->tstamp) to schedule traffic transmission based on absolute >>> time. >>> >>> For some workloads, just bandwidth enforcement is not enough, and >>> precise control of the transmission of packets is necessary. >>> >>> Example: >>> >>> $ tc qdisc replace dev enp2s0 parent root handle 100 mqprio num_tc 3 \ >> >> handle 100:0 ? >> >>> map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@0 1@1 2@2 hw 0 >>> >>> $ tc qdisc add dev enp2s0 parent 100:1 tbs delta 60000 clockid 11 offload 1 >>> >>> >>> In this example, the Qdisc will try to enable offloading (offload 1) >>> the control of the transmission time to the network adapter, the >>> time stamp in socket are in reference to the clockid '11' (CLOCK_TAI) >>> and packets leave the Qdisc "delta" (60000) nanoseconds before its >>> transmission time. >>> >> >> >>> When offloading is disabled, the network adapter will ignore the >>> sk_buff time stamp, and so, the transmission time will be only "best >>> effort" from the Qdisc. >>> >> >> General comments: >> 1) iproute2: Avoid magic numbers like 1 or 11 please; "offload" >> (without 1) and "TAI" will be more human friendly. >> >> 2) Experience shows that adding padding fields in the control structs >> implies they will _never ever_ be used. That was not design intent >> for netlink but over years shit like that has happened. >> Maybe look at using a 32 bitmap? It is more "future proof". >> You seem to only have 2-3 flags but it gives you opportunity >> to add more changes later. If you are 100% sure youll never need >> it - then maybe just move the tc_tbs_qopt::offload to the end of >> of the struct. >> >> 3)It would be helpful for debugging to increment some stats other >> than drop counters on enqueu/dequeue obsolete packet drop. Maybe use >> overlimits for the dequeu drops (in addition)? >> >> 4) I may be misreading things - but did you need to reset the >> watchdog on dequeue? It is already being kicked for every incoming packet. >> >> cheers, >> jamal >
