From: David Ahern <firstname.lastname@example.org> To: Jason Gunthorpe <email@example.com> Cc: Parav Pandit <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, Jiri Pirko <email@example.com>, "firstname.lastname@example.org" <email@example.com>, Leon Romanovsky <firstname.lastname@example.org>, Saeed Mahameed <email@example.com>, "firstname.lastname@example.org" <email@example.com>, "firstname.lastname@example.org" <email@example.com>, Vu Pham <firstname.lastname@example.org> Subject: Re: [PATCH net-next 03/13] devlink: Support add and delete devlink port Date: Wed, 18 Nov 2020 12:36:26 -0700 [thread overview] Message-ID: <email@example.com> (raw) In-Reply-To: <20201118183830.GA917484@nvidia.com> On 11/18/20 11:38 AM, Jason Gunthorpe wrote: > On Wed, Nov 18, 2020 at 11:03:24AM -0700, David Ahern wrote: > >> With Connectx-4 Lx for example the netdev can have at most 63 queues > > What netdev calls a queue is really a "can the device deliver > interrupts and packets to a given per-CPU queue" and covers a whole > spectrum of smaller limits like RSS scheme, # of available interrupts, > ability of the device to create queues, etc. > > CX4Lx can create a huge number of queues, but hits one of these limits > that mean netdev's specific usage can't scale up. Other stuff like > RDMA doesn't have the same limits, and has tonnes of queues. > > What seems to be needed is a resource controller concept like cgroup > has for processes. The system is really organized into a tree: > > physical device > mlx5_core > / | \ \ (aux bus) > netdev rdma vdpa SF etc > | (aux bus) > mlx5_core > / \ (aux bus) > netdev vdpa > > And it does make a lot of sense to start to talk about limits at each > tree level. > > eg the top of the tree may have 128 physical interrupts. With 128 CPU > cores that isn't enough interrupts to support all of those things > concurrently. > > So the user may want to configure: > - The first level netdev only gets 64, > - 3rd level mlx5_core gets 32 > - Final level vdpa gets 8 > > Other stuff has to fight it out with the remaining shared interrupts. > > In netdev land # of interrupts governs # of queues > > For RDMA # of interrupts limits the CPU affinities for queues > > VPDA limits the # of VMs that can use VT-d > > The same story repeats for other less general resources, mlx5 also > has consumption of limited BAR space, and consumption of some limited > memory elements. These numbers are much bigger and may not need > explicit governing, but the general concept holds. > > It would be very nice if the limit could be injected when the aux > device is created but before the driver is bound. I'm not sure how to > manage that though.. > > I assume other devices will be different, maybe some devices have a > limit on the number of total queues, or a limit on the number of > VDPA or RDMA devices. > > Jason > A lot of low level resource details that need to be summarized into a nicer user / config perspective to specify limits / allocations. Thanks for the detailed response.
next prev parent reply other threads:[~2020-11-18 19:36 UTC|newest] Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-12 19:24 [PATCH net-next 00/13] Add mlx5 subfunction support Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 01/13] devlink: Prepare code to fill multiple port function attributes Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 02/13] devlink: Introduce PCI SF port flavour and port attribute Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 03/13] devlink: Support add and delete devlink port Parav Pandit 2020-11-18 16:21 ` David Ahern 2020-11-18 17:02 ` Parav Pandit 2020-11-18 18:03 ` David Ahern 2020-11-18 18:38 ` Jason Gunthorpe 2020-11-18 19:36 ` David Ahern [this message] 2020-11-18 20:42 ` Jason Gunthorpe 2020-11-18 19:22 ` Parav Pandit 2020-11-19 0:41 ` Jacob Keller 2020-11-19 1:17 ` David Ahern 2020-11-19 1:56 ` Samudrala, Sridhar 2020-11-19 0:52 ` Jacob Keller 2020-11-12 19:24 ` [PATCH net-next 04/13] devlink: Support get and set state of port function Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 05/13] devlink: Avoid global devlink mutex, use per instance reload lock Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 06/13] devlink: Introduce devlink refcount to reduce scope of global devlink_mutex Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 07/13] net/mlx5: SF, Add auxiliary device support Parav Pandit 2020-12-07 2:48 ` David Ahern 2020-12-07 4:53 ` Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 08/13] net/mlx5: SF, Add auxiliary device driver Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 09/13] net/mlx5: E-switch, Prepare eswitch to handle SF vport Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 10/13] net/mlx5: E-switch, Add eswitch helpers for " Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 11/13] net/mlx5: SF, Add SF configuration hardware commands Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 12/13] net/mlx5: SF, Add port add delete functionality Parav Pandit 2020-11-12 19:24 ` [PATCH net-next 13/13] net/mlx5: SF, Port function state change support Parav Pandit 2020-11-16 22:52 ` [PATCH net-next 00/13] Add mlx5 subfunction support Jakub Kicinski 2020-11-17 0:06 ` Saeed Mahameed 2020-11-17 1:58 ` Jakub Kicinski 2020-11-17 4:08 ` Parav Pandit 2020-11-17 17:11 ` Jakub Kicinski 2020-11-17 18:49 ` Jason Gunthorpe 2020-11-19 2:14 ` Jakub Kicinski 2020-11-19 4:35 ` David Ahern 2020-11-19 5:57 ` Saeed Mahameed 2020-11-20 1:31 ` Jakub Kicinski 2020-11-25 5:33 ` David Ahern 2020-11-25 6:00 ` Parav Pandit 2020-11-25 14:37 ` David Ahern 2020-11-20 1:29 ` Jakub Kicinski 2020-11-20 17:58 ` Alexander Duyck 2020-11-20 19:04 ` Samudrala, Sridhar 2020-11-23 21:51 ` Saeed Mahameed 2020-11-24 7:01 ` Jason Wang 2020-11-24 7:05 ` Jason Wang 2020-11-19 6:12 ` Saeed Mahameed 2020-11-19 8:25 ` Parav Pandit 2020-11-20 1:35 ` Jakub Kicinski 2020-11-20 3:34 ` Parav Pandit 2020-11-17 18:50 ` Parav Pandit 2020-11-19 2:23 ` Jakub Kicinski 2020-11-19 6:22 ` Saeed Mahameed 2020-11-19 14:00 ` Jason Gunthorpe 2020-11-20 3:35 ` Jakub Kicinski 2020-11-20 3:50 ` Parav Pandit 2020-11-20 16:16 ` Jason Gunthorpe
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