Yeah I got the clear picture. Eventually MSIX can be routed to worker cores which can wake on eventfd, hence unix-epoll-input node required.
Thanks, Nitin From: Damjan Marion <dmar...@me.com> Sent: Wednesday, February 5, 2020 3:08 PM To: Nitin Saxena <nsax...@marvell.com> Cc: vpp-dev@lists.fd.io Subject: Re: [EXT] [vpp-dev] Regarding unix_epoll_input on worker cores Yes, but you keep interrupts disabled while in polling mode. At the point when traffic load goes down, you can switch to interrupt mode by switching MSI-X interrupts on. We already have that functionality today, only issue is that interrupts are routed to main thread, so it may happen that worker is sleeping and that will cause delay in taking packet from the rx queue handled by that worker... On 5 Feb 2020, at 10:24, Nitin Saxena <nsax...@marvell.com<mailto:nsax...@marvell.com>> wrote: >> No, there is no need to change default state. State can be changed during >> runtime... That part I understand. I realized that AVF supports MSIX interrupts hence native plugin can easily leverage this feature (provided hardware supports MSIX per RQ) Thanks, Nitin From: vpp-dev@lists.fd.io<mailto:vpp-dev@lists.fd.io> <vpp-dev@lists.fd.io<mailto:vpp-dev@lists.fd.io>> On Behalf Of Damjan Marion via Lists.Fd.Io Sent: Wednesday, February 5, 2020 2:32 PM To: Nitin Saxena <nsax...@marvell.com<mailto:nsax...@marvell.com>> Cc: vpp-dev@lists.fd.io<mailto:vpp-dev@lists.fd.io> Subject: Re: [EXT] Re: [vpp-dev] Regarding unix_epoll_input on worker cores No, there is no need to change default state. State can be changed during runtime... — Damjan On 5 Feb 2020, at 09:54, Nitin Saxena <nsax...@marvell.com<mailto:nsax...@marvell.com>> wrote: Thanks Damjan. Then I think there will be plan to change default state of INPUT nodes from POLLING to INTERRUPTIBLE. I think it is required to enable this feature at some point. Thanks, Nitin From: Damjan Marion <dmar...@me.com<mailto:dmar...@me.com>> Sent: Wednesday, February 5, 2020 2:00 PM To: Nitin Saxena <nsax...@marvell.com<mailto:nsax...@marvell.com>> Cc: vpp-dev <vpp-dev@lists.fd.io<mailto:vpp-dev@lists.fd.io>> Subject: [EXT] Re: [vpp-dev] Regarding unix_epoll_input on worker cores External Email ________________________________ There are 2 use cases: - delivering RX queue interrupts directpy to the worker which handles specific queue - waking up worker thread over eventfd None of them is used today, but it should be at some point... -- DAmjan On 5 Feb 2020, at 08:39, Nitin Saxena <nsax...@marvell.com<mailto:nsax...@marvell.com>> wrote: Hi, I understand the purpose of unix-epoll-input PRE_INPUT node on main thread but I am not able to envision why it is required on worker core. The way I see it all clib_file_xx() operations are on main core. It will be helpful if any scenario can be explained where presence of unix-epoll-input() on worker core solves the purpose Thanks, Nitin -- Damjan -- Damjan
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