| Message ID | 20240801093115.8553-1-michal.swiatkowski@linux.intel.com |
|---|---|
| Headers | show |
| Series | ice: managing MSI-X in driver | expand |
On 8/1/24 11:31, Michal Swiatkowski wrote: > Hi, > > It is another try to allow user to manage amount of MSI-X used for each > feature in ice. First was via devlink resources API, it wasn't accepted > in upstream. Also static MSI-X allocation using devlink resources isn't > really user friendly. > > This try is using more dynamic way. "Dynamic" across whole kernel when > platform supports it and "dynamic" across the driver when not. > > To achieve that reuse global devlink parameter pf_msix_max and > pf_msix_min. It fits how ice hardware counts MSI-X. In case of ice amount > of MSI-X reported on PCI is a whole MSI-X for the card (with MSI-X for > VFs also). Having pf_msix_max allow user to statically set how many > MSI-X he wants on PF and how many should be reserved for VFs. > > pf_msix_min is used to set minimum number of MSI-X with which ice driver > should probe correctly. > > Meaning of this field in case of dynamic vs static allocation: > - on system with dynamic MSI-X allocation support > * alloc pf_msix_min as static, rest will be allocated dynamically > - on system without dynamic MSI-X allocation support > * try alloc pf_msix_max as static, minimum acceptable result is > pf_msix_min > > As Jesse and Piotr suggested pf_msix_max and pf_msix_min can (an > probably should) be stored in NVM. This patchset isn't implementing > that. > > Dynamic (kernel or driver) way means that splitting MSI-X across the > RDMA and eth in case there is a MSI-X shortage isn't correct. Can work > when dynamic is only on driver site, but can't when dynamic is on kernel > site. > > Let's remove this code and move to MSI-X allocation feature by feature. > If there is no more MSI-X for a feature, a feature is working with less > MSI-X or it is turned off. > > There is a regression here. With MSI-X splitting user can run RDMA and > eth even on system with not enough MSI-X. Now only eth will work. RDMA > can be turned on by changing number of PF queues (lowering) and reprobe > RDMA driver. > > Example: > 72 CPU number, eth, RDMA and flow director (1 MSI-X), 1 MSI-X for OICR > on PF, and 1 more for RDMA. Card is using 1 + 72 + 1 + 72 + 1 = 147. > > We set pf_msix_min = 2, pf_msix_max = 128 > > OICR: 1 > eth: 72 > RDMA: 128 - 73 = 55 > flow director: turned off not enough MSI-X > > We can change number of queues on pf to 36 and do devlink reinit > > OICR: 1 > eth: 36 > RDMA: 73 > flow director: 1 > > We can also (implemented in "ice: enable_rdma devlink param") turned > RDMA off. > > OICR: 1 > eth: 72 > RDMA: 0 (turned off) > flow director: 1 > > Maybe flow director should have higher priority than RDMA? It needs only > 1 MSI-X, so it seems more logic to lower RDMA by one then maxing MSI-X > on RDMA and turning off flow director (as default). sounds better, less surprising, with only RDMA being affected by this series as "regression" > > After this changes we have a static base vector for SRIOV (SIOV probably > in the feature). Last patch from this series is simplifying managing VF > MSI-X code based on static vector. > > Now changing queues using ethtool is also changing MSI-X. If there is > enough MSI-X it is always one to one. When there is not enough there > will be more queues than MSI-X. There is a lack of ability to set how > many queues should be used per MSI-X. Maybe we should introduce another > ethtool param for it? Sth like queues_per_vector? Our 1:1 mapping was too rigid solution (but performant), I like MSI-Xes being kept as a detail and [setting of them] decoupled from being mandatory on [at least some] flows. Tuning the mapping could be useful, esp in heterotelic scenarios (like keeping XDP stuff separate). Could be left for the future. What happens when user decreases number of MSI-X, queues will just get remapped to other? > > v1 --> v2: [1] > * change permanent MSI-X cmode parameters to driverinit > * remove locking during devlink parameter registration (it is now > locked for whole init/deinit part) > > [1] https://lore.kernel.org/netdev/20240213073509.77622-1-michal.swiatkowski@linux.intel.com/ > > Michal Swiatkowski (7): > ice: devlink PF MSI-X max and min parameter > ice: remove splitting MSI-X between features > ice: get rid of num_lan_msix field > ice, irdma: move interrupts code to irdma > ice: treat dyn_allowed only as suggestion > ice: enable_rdma devlink param > ice: simplify VF MSI-X managing > > drivers/infiniband/hw/irdma/hw.c | 2 - > drivers/infiniband/hw/irdma/main.c | 46 ++- > drivers/infiniband/hw/irdma/main.h | 3 + > .../net/ethernet/intel/ice/devlink/devlink.c | 75 ++++- > drivers/net/ethernet/intel/ice/ice.h | 21 +- > drivers/net/ethernet/intel/ice/ice_base.c | 10 +- > drivers/net/ethernet/intel/ice/ice_ethtool.c | 8 +- > drivers/net/ethernet/intel/ice/ice_idc.c | 64 +--- > drivers/net/ethernet/intel/ice/ice_irq.c | 277 ++++++------------ > drivers/net/ethernet/intel/ice/ice_irq.h | 13 +- > drivers/net/ethernet/intel/ice/ice_lib.c | 36 ++- > drivers/net/ethernet/intel/ice/ice_sriov.c | 153 +--------- > include/linux/net/intel/iidc.h | 2 + > 13 files changed, 287 insertions(+), 423 deletions(-) >
On Fri, Aug 02, 2024 at 02:41:54PM +0200, Przemek Kitszel wrote: > On 8/1/24 11:31, Michal Swiatkowski wrote: > > Hi, > > > > It is another try to allow user to manage amount of MSI-X used for each > > feature in ice. First was via devlink resources API, it wasn't accepted > > in upstream. Also static MSI-X allocation using devlink resources isn't > > really user friendly. > > > > This try is using more dynamic way. "Dynamic" across whole kernel when > > platform supports it and "dynamic" across the driver when not. > > > > To achieve that reuse global devlink parameter pf_msix_max and > > pf_msix_min. It fits how ice hardware counts MSI-X. In case of ice amount > > of MSI-X reported on PCI is a whole MSI-X for the card (with MSI-X for > > VFs also). Having pf_msix_max allow user to statically set how many > > MSI-X he wants on PF and how many should be reserved for VFs. > > > > pf_msix_min is used to set minimum number of MSI-X with which ice driver > > should probe correctly. > > > > Meaning of this field in case of dynamic vs static allocation: > > - on system with dynamic MSI-X allocation support > > * alloc pf_msix_min as static, rest will be allocated dynamically > > - on system without dynamic MSI-X allocation support > > * try alloc pf_msix_max as static, minimum acceptable result is > > pf_msix_min > > > > As Jesse and Piotr suggested pf_msix_max and pf_msix_min can (an > > probably should) be stored in NVM. This patchset isn't implementing > > that. > > > > Dynamic (kernel or driver) way means that splitting MSI-X across the > > RDMA and eth in case there is a MSI-X shortage isn't correct. Can work > > when dynamic is only on driver site, but can't when dynamic is on kernel > > site. > > > > Let's remove this code and move to MSI-X allocation feature by feature. > > If there is no more MSI-X for a feature, a feature is working with less > > MSI-X or it is turned off. > > > > There is a regression here. With MSI-X splitting user can run RDMA and > > eth even on system with not enough MSI-X. Now only eth will work. RDMA > > can be turned on by changing number of PF queues (lowering) and reprobe > > RDMA driver. > > > > Example: > > 72 CPU number, eth, RDMA and flow director (1 MSI-X), 1 MSI-X for OICR > > on PF, and 1 more for RDMA. Card is using 1 + 72 + 1 + 72 + 1 = 147. > > > > We set pf_msix_min = 2, pf_msix_max = 128 > > > > OICR: 1 > > eth: 72 > > RDMA: 128 - 73 = 55 > > flow director: turned off not enough MSI-X > > > > We can change number of queues on pf to 36 and do devlink reinit > > > > OICR: 1 > > eth: 36 > > RDMA: 73 > > flow director: 1 > > > > We can also (implemented in "ice: enable_rdma devlink param") turned > > RDMA off. > > > > OICR: 1 > > eth: 72 > > RDMA: 0 (turned off) > > flow director: 1 > > > > Maybe flow director should have higher priority than RDMA? It needs only > > 1 MSI-X, so it seems more logic to lower RDMA by one then maxing MSI-X > > on RDMA and turning off flow director (as default). > > sounds better, less surprising, with only RDMA being affected by this > series as "regression" > Sounds reasonable > > > > After this changes we have a static base vector for SRIOV (SIOV probably > > in the feature). Last patch from this series is simplifying managing VF > > MSI-X code based on static vector. > > > > Now changing queues using ethtool is also changing MSI-X. If there is > > enough MSI-X it is always one to one. When there is not enough there > > will be more queues than MSI-X. There is a lack of ability to set how > > many queues should be used per MSI-X. Maybe we should introduce another > > ethtool param for it? Sth like queues_per_vector? > > Our 1:1 mapping was too rigid solution (but performant), I like MSI-Xes > being kept as a detail and [setting of them] decoupled from being > mandatory on [at least some] flows. Tuning the mapping could be useful, > esp in heterotelic scenarios (like keeping XDP stuff separate). Could be > left for the future. > > What happens when user decreases number of MSI-X, queues will just get > remapped to other? > Yes, queue will be remapped > > > > v1 --> v2: [1] > > * change permanent MSI-X cmode parameters to driverinit > > * remove locking during devlink parameter registration (it is now > > locked for whole init/deinit part) > > > > [1] https://lore.kernel.org/netdev/20240213073509.77622-1-michal.swiatkowski@linux.intel.com/ > > > > Michal Swiatkowski (7): > > ice: devlink PF MSI-X max and min parameter > > ice: remove splitting MSI-X between features > > ice: get rid of num_lan_msix field > > ice, irdma: move interrupts code to irdma > > ice: treat dyn_allowed only as suggestion > > ice: enable_rdma devlink param > > ice: simplify VF MSI-X managing > > > > drivers/infiniband/hw/irdma/hw.c | 2 - > > drivers/infiniband/hw/irdma/main.c | 46 ++- > > drivers/infiniband/hw/irdma/main.h | 3 + > > .../net/ethernet/intel/ice/devlink/devlink.c | 75 ++++- > > drivers/net/ethernet/intel/ice/ice.h | 21 +- > > drivers/net/ethernet/intel/ice/ice_base.c | 10 +- > > drivers/net/ethernet/intel/ice/ice_ethtool.c | 8 +- > > drivers/net/ethernet/intel/ice/ice_idc.c | 64 +--- > > drivers/net/ethernet/intel/ice/ice_irq.c | 277 ++++++------------ > > drivers/net/ethernet/intel/ice/ice_irq.h | 13 +- > > drivers/net/ethernet/intel/ice/ice_lib.c | 36 ++- > > drivers/net/ethernet/intel/ice/ice_sriov.c | 153 +--------- > > include/linux/net/intel/iidc.h | 2 + > > 13 files changed, 287 insertions(+), 423 deletions(-) > > >