> -----Original Message----- > From: Kevin Traynor [mailto:[email protected]] > Sent: Thursday, November 23, 2017 1:05 PM > To: O Mahony, Billy <[email protected]>; [email protected]; > [email protected] > Subject: Re: [ovs-dev] [RFC PATCH v2] dpif-netdev: Add port/queue > tiebreaker to rxq_cycle_sort. > > On 11/23/2017 10:42 AM, O Mahony, Billy wrote: > > Hi Kevin, > > > > My 2c below.. > > > > /Billy > > > >> -----Original Message----- > >> From: [email protected] [mailto:ovs-dev- > >> [email protected]] On Behalf Of Kevin Traynor > >> Sent: Wednesday, November 22, 2017 7:11 PM > >> To: [email protected]; [email protected] > >> Subject: [ovs-dev] [RFC PATCH v2] dpif-netdev: Add port/queue > >> tiebreaker to rxq_cycle_sort. > >> > >> rxq_cycle_sort is used to sort the rx queues by their measured number of > cycles. > >> In the event that they are equal 0 could be returned. > >> However, it is observed that returning 0 results in a different sort > >> order on Windows/Linux. This is ok in practice but it causes a unit > >> test failure for > >> "1007: PMD - pmd-cpu-mask/distribution of rx queues" on Windows. > >> > >> In order to have a consistent sort result, introduce a tiebreaker of > port/queue. > >> > >> Fixes: 655856ef39b9 ("dpif-netdev: Change rxq_scheduling to use rxq > >> processing > >> cycles.") > >> Reported-by: Alin Gabriel Serdean <[email protected]> > >> Signed-off-by: Kevin Traynor <[email protected]> > >> --- > >> > >> v2: Inadvertently reversed the order for non-tiebreak cases in v1. Fix > >> that. > >> > >> lib/dpif-netdev.c | 15 ++++++++++++--- > >> 1 file changed, 12 insertions(+), 3 deletions(-) > >> > >> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c index > >> 0a62630..57451e9 100644 > >> --- a/lib/dpif-netdev.c > >> +++ b/lib/dpif-netdev.c > >> @@ -3452,4 +3452,5 @@ rxq_cycle_sort(const void *a, const void *b) > >> uint64_t total_qa, total_qb; > >> unsigned i; > >> + int winner = 1; > >> > >> qa = *(struct dp_netdev_rxq **) a; @@ -3464,8 +3465,16 @@ > >> rxq_cycle_sort(const void *a, const void *b) > >> dp_netdev_rxq_set_cycles(qb, RXQ_CYCLES_PROC_HIST, total_qb); > >> > > [[BO'M]] > > I think it's worth adding a comment to state this compare function never > return's 0 and that the reason for this (the sort order difference on > different > OSs). > > > > Sure, I will add this for PATCH version. > > > Also the function should probably be called rxq_cycle_compare as its really > comparing entries rather than sorting a list of entries And it's used as the > compar arg to qsort. > > > > yeah, I guess it would be a better name. It would be a separate patch as it's > an unrelated change, but I might submit at same time as making this PATCH. > > thanks, > Kevin. > [Alin Serdean] I applied the patch and the test passes now. Thanks a lot Kevin.
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