Messages in this thread | | | Date | Tue, 30 Oct 2012 07:24:15 -0700 | From | Stephen Hemminger <> | Subject | Re: [PATCH RFC] pkt_sched: enable QFQ to support TSO/GSO |
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On Tue, 30 Oct 2012 07:00:56 +0100 Paolo Valente <paolo.valente@unimore.it> wrote:
> Hi, > if the max packet size for some class (configured through tc) is > violated by the actual size of the packets of that class, then QFQ > would not schedule classes correctly, and the data structures > implementing the bucket lists may get corrupted. This problem occurs > with TSO/GSO even if the max packet size is set to the MTU, and is, > e.g., the cause of the failure reported in [1]. Two patches have been > proposed to solve this problem in [2], one of them is a preliminary > version of this patch. > > This patch addresses the above issues by: 1) setting QFQ parameters to > proper values for supporting TSO/GSO (in particular, setting the > maximum possible packet size to 64KB), 2) automatically increasing the > max packet size for a class, lmax, when a packet with a larger size > than the current value of lmax arrives. > > The drawback of the first point is that the maximum weight for a class > is now limited to 4096, which is equal to 1/16 of the maximum weight > sum. > > Finally, this patch also forcibly caps the timestamps of a class if > they are too high to be stored in the bucket list. This capping, taken > from QFQ+ [3], handles the unfrequent case described in the comment to > the function slot_insert. > > [1] http://marc.info/?l=linux-netdev&m=134968777902077&w=2 > [2] http://marc.info/?l=linux-netdev&m=135096573507936&w=2 > [3] http://marc.info/?l=linux-netdev&m=134902691421670&w=2 > > Signed-off-by: Paolo Valente <paolo.valente@unimore.it> > Tested-by: Cong Wang <amwang@redhat.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
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