From: Michal Swiatkowski <[email protected]> Date: Fri, 17 Oct 2025 09:30:44 +0200
> On Fri, Oct 17, 2025 at 07:03:31AM +0200, Przemek Kitszel wrote: >> On 10/16/25 17:36, Alexander Lobakin wrote: >>> From: Michal Swiatkowski <[email protected]> >>> Date: Thu, 16 Oct 2025 08:22:50 +0200 >>> >>>> On some high-core systems loading ice driver with default values can >>>> lead to queue/irq exhaustion. It will result in no additional resources >>>> for SR-IOV. >>>> >>>> In most cases there is no performance reason for more than 64 queues. >>>> Limit the default value to 64. Still, using ethtool the number of >>>> queues can be changed up to num_online_cpus(). >>>> >>>> This change affects only the default queue amount on systems with more >>>> than 64 cores. >>>> >>>> Reviewed-by: Jacob Keller <[email protected]> >>>> Signed-off-by: Michal Swiatkowski <[email protected]> >>>> --- >>>> drivers/net/ethernet/intel/ice/ice.h | 20 ++++++++++++++++++++ >>>> drivers/net/ethernet/intel/ice/ice_irq.c | 6 ++++-- >>>> drivers/net/ethernet/intel/ice/ice_lib.c | 8 ++++---- >>>> 3 files changed, 28 insertions(+), 6 deletions(-) >>>> >>>> diff --git a/drivers/net/ethernet/intel/ice/ice.h >>>> b/drivers/net/ethernet/intel/ice/ice.h >>>> index 3d4d8b88631b..354ec2950ff3 100644 >>>> --- a/drivers/net/ethernet/intel/ice/ice.h >>>> +++ b/drivers/net/ethernet/intel/ice/ice.h >>>> @@ -1133,4 +1133,24 @@ static inline struct ice_hw >>>> *ice_get_primary_hw(struct ice_pf *pf) >>>> else >>>> return &pf->adapter->ctrl_pf->hw; >>>> } >>>> + >>>> +/** >>>> + * ice_capped_num_cpus - normalize the number of CPUs to a reasonable >>>> limit >>>> + * >>>> + * This function returns the number of online CPUs, but caps it at >>>> suitable >>>> + * default to prevent excessive resource allocation on systems with very >>>> high >>>> + * CPU counts. >>>> + * >>>> + * Note: suitable default is currently at 64, which is reflected in >>>> default_cpus >>>> + * constant. In most cases there is no much benefit for more than 64 and >>>> it is a >>>> + * power of 2 number. >>>> + * >>>> + * Return: number of online CPUs, capped at suitable default. >>>> + */ >>>> +static inline u16 ice_capped_num_cpus(void) >>>> +{ >>>> + const int default_cpus = 64; >>> >>> Maybe we should just use netif_get_num_default_rss_queues() like I did >>> in idpf? >>> >>> Or it still can be too high e.g. on clusters with > 256 CPUs? >> >> good point, >> perhaps we should both use it and change the (kernel) func to cap at 64 >> > > Sounds good, thanks for pointing the function. > > Do you think it is ok to cap the generic function? Maybe other vendors > want more default queues. Nah I don't think it's a good idea to hardcode any numbers in the generic function. > > What about capping netif_get_num_default_rss_queues() at 64 just for > ice? netif_get_num_default_rss_queues() returns *half* of the number of *physical* cores. I.e. it will return something bigger than 64 only in case of > 256 threads in the system (considering SMT). Do we need to still cap this to 64 in ice at all? Thanks, Olek
