| Message ID | 1556626682-28858-1-git-send-email-david.marchand@redhat.com |
|---|---|
| Headers | show |
| Series | Quicker pmd threads reloads | expand |
On 30.04.2019 15:17, David Marchand wrote: > We have been testing the rebalance code in different situations while > having traffic going through OVS. > Those tests have shown that part of the observed packets losses is due to > some time wasted in signaling/waiting for the pmd threads to reload their > polling configurations. > > This RFC series is an attempt at getting pmd threads reloads quicker and > more deterministic. > Do you have some performance data to share? Best regards, Ilya Maximets.
Hello Ilya, Thanks for looking at this series. On Mon, May 6, 2019 at 5:22 PM Ilya Maximets <i.maximets@samsung.com> wrote: > On 30.04.2019 15:17, David Marchand wrote: > > We have been testing the rebalance code in different situations while > > having traffic going through OVS. > > Those tests have shown that part of the observed packets losses is due to > > some time wasted in signaling/waiting for the pmd threads to reload their > > polling configurations. > > > > This RFC series is an attempt at getting pmd threads reloads quicker and > > more deterministic. > > > > Do you have some performance data to share? > During our testing of rebalance, we were tracking packets losses with traffic running during a rebalance. I focused on the cycles spent in the transition between two polling configurations. I triggered 1000 rebalances on each patch of this series, with rte_rdtsc() probes in reconfigure_datapath() / pmd_thread_main(). Between the moment we stop polling in a pmd for a given configuration and the moment we start polling again in the new configuration: - before the patches, a pmd would spend 140k/330k/3 000k cycles (minimum/average/maximum). - after the patches, a pmd would spend 13k/20k/43k cycles. Originally, the numbers are highly volatile: I got a 20 000k cycles in a previous test run (which translated to 28k lost packets with the ofrules I had). I had a look at your comments, I will come with the fixes later this week (tomorrow is off in France).