[PATCH iwl-next v2] ice: use netif_get_num_default_rss_queues()

[PATCH iwl-next v2] ice: use netif_get_num_default_rss_queues()

[Michal Swiatkowski]

On some high-core systems (like AMD EPYC Bergamo, Intel Clearwater
Forest) 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 half
num_cpus(). Limit the default value to it using generic
netif_get_num_default_rss_queues().

Still, using ethtool the number of queues can be changed up to
num_online_cpus(). It can be done by calling:
$ethtool -L ethX combined max_cpu

This change affects only the default queue amount.

Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
---
v1 --> v2:
 * Follow Olek's comment and switch from custom limiting to the generic
   netif_...() function.
 * Add more info in commit message (Paul)
 * Dropping RB tags, as it is different patch now
---
 drivers/net/ethernet/intel/ice/ice_irq.c |  5 +++--
 drivers/net/ethernet/intel/ice/ice_lib.c | 12 ++++++++----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_irq.c b/drivers/net/ethernet/intel/ice/ice_irq.c
index 30801fd375f0..1d9b2d646474 100644
--- a/drivers/net/ethernet/intel/ice/ice_irq.c
+++ b/drivers/net/ethernet/intel/ice/ice_irq.c
@@ -106,9 +106,10 @@ static struct ice_irq_entry *ice_get_irq_res(struct ice_pf *pf,
 #define ICE_RDMA_AEQ_MSIX 1
 static int ice_get_default_msix_amount(struct ice_pf *pf)
 {
-	return ICE_MIN_LAN_OICR_MSIX + num_online_cpus() +
+	return ICE_MIN_LAN_OICR_MSIX + netif_get_num_default_rss_queues() +
 	       (test_bit(ICE_FLAG_FD_ENA, pf->flags) ? ICE_FDIR_MSIX : 0) +
-	       (ice_is_rdma_ena(pf) ? num_online_cpus() + ICE_RDMA_AEQ_MSIX : 0);
+	       (ice_is_rdma_ena(pf) ? netif_get_num_default_rss_queues() +
+				      ICE_RDMA_AEQ_MSIX : 0);
 }
 
 /**
diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index bac481e8140d..e366d089bef9 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -159,12 +159,14 @@ static void ice_vsi_set_num_desc(struct ice_vsi *vsi)
 
 static u16 ice_get_rxq_count(struct ice_pf *pf)
 {
-	return min(ice_get_avail_rxq_count(pf), num_online_cpus());
+	return min(ice_get_avail_rxq_count(pf),
+		   netif_get_num_default_rss_queues());
 }
 
 static u16 ice_get_txq_count(struct ice_pf *pf)
 {
-	return min(ice_get_avail_txq_count(pf), num_online_cpus());
+	return min(ice_get_avail_txq_count(pf),
+		   netif_get_num_default_rss_queues());
 }
 
 /**
@@ -907,13 +909,15 @@ static void ice_vsi_set_rss_params(struct ice_vsi *vsi)
 		if (vsi->type == ICE_VSI_CHNL)
 			vsi->rss_size = min_t(u16, vsi->num_rxq, max_rss_size);
 		else
-			vsi->rss_size = min_t(u16, num_online_cpus(),
+			vsi->rss_size = min_t(u16,
+					      netif_get_num_default_rss_queues(),
 					      max_rss_size);
 		vsi->rss_lut_type = ICE_LUT_PF;
 		break;
 	case ICE_VSI_SF:
 		vsi->rss_table_size = ICE_LUT_VSI_SIZE;
-		vsi->rss_size = min_t(u16, num_online_cpus(), max_rss_size);
+		vsi->rss_size = min_t(u16, netif_get_num_default_rss_queues(),
+				      max_rss_size);
 		vsi->rss_lut_type = ICE_LUT_VSI;
 		break;
 	case ICE_VSI_VF:
-- 
2.49.0

RE: [Intel-wired-lan] [PATCH iwl-next v2] ice: use netif_get_num_default_rss_queues()

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf
> Of Michal Swiatkowski
> Sent: Tuesday, October 28, 2025 8:07 AM
> To: intel-wired-lan@lists.osuosl.org
> Cc: netdev@vger.kernel.org; pmenzel@molgen.mpg.de; Lobakin, Aleksander
> <aleksander.lobakin@intel.com>; Kitszel, Przemyslaw
> <przemyslaw.kitszel@intel.com>; Keller, Jacob E
> <jacob.e.keller@intel.com>; Michal Swiatkowski
> <michal.swiatkowski@linux.intel.com>
> Subject: [Intel-wired-lan] [PATCH iwl-next v2] ice: use
> netif_get_num_default_rss_queues()
> 
> On some high-core systems (like AMD EPYC Bergamo, Intel Clearwater
> Forest) 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 half
> num_cpus(). Limit the default value to it using generic
> netif_get_num_default_rss_queues().
> 
> Still, using ethtool the number of queues can be changed up to
> num_online_cpus(). It can be done by calling:
> $ethtool -L ethX combined max_cpu
> 
It could be nice to use $(nproc)?
 $ ethtool -L ethX combined $(nproc)

> This change affects only the default queue amount.
> 
> Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
> ---
> v1 --> v2:
>  * Follow Olek's comment and switch from custom limiting to the
> generic
>    netif_...() function.
>  * Add more info in commit message (Paul)
>  * Dropping RB tags, as it is different patch now
> ---
>  drivers/net/ethernet/intel/ice/ice_irq.c |  5 +++--
>  drivers/net/ethernet/intel/ice/ice_lib.c | 12 ++++++++----
>  2 files changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_irq.c
> b/drivers/net/ethernet/intel/ice/ice_irq.c
> index 30801fd375f0..1d9b2d646474 100644
> --- a/drivers/net/ethernet/intel/ice/ice_irq.c
> +++ b/drivers/net/ethernet/intel/ice/ice_irq.c
> @@ -106,9 +106,10 @@ static struct ice_irq_entry
> *ice_get_irq_res(struct ice_pf *pf,
>  #define ICE_RDMA_AEQ_MSIX 1
>  static int ice_get_default_msix_amount(struct ice_pf *pf)
>  {
> -	return ICE_MIN_LAN_OICR_MSIX + num_online_cpus() +
> +	return ICE_MIN_LAN_OICR_MSIX +
> netif_get_num_default_rss_queues() +
>  	       (test_bit(ICE_FLAG_FD_ENA, pf->flags) ? ICE_FDIR_MSIX :
> 0) +
> -	       (ice_is_rdma_ena(pf) ? num_online_cpus() +
> ICE_RDMA_AEQ_MSIX : 0);
> +	       (ice_is_rdma_ena(pf) ?
> netif_get_num_default_rss_queues() +
> +				      ICE_RDMA_AEQ_MSIX : 0);
>  }
> 
>  /**
> diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c
> b/drivers/net/ethernet/intel/ice/ice_lib.c
> index bac481e8140d..e366d089bef9 100644
> --- a/drivers/net/ethernet/intel/ice/ice_lib.c
> +++ b/drivers/net/ethernet/intel/ice/ice_lib.c
> @@ -159,12 +159,14 @@ static void ice_vsi_set_num_desc(struct ice_vsi
> *vsi)
> 
>  static u16 ice_get_rxq_count(struct ice_pf *pf)
>  {
> -	return min(ice_get_avail_rxq_count(pf), num_online_cpus());
> +	return min(ice_get_avail_rxq_count(pf),
> +		   netif_get_num_default_rss_queues());
>  }
min(a, b) resolves to the type of the expression, which here will be int due to netif_get_num_default_rss_queues() returning int. 
That implicitly truncates to u16 on return.
What do you think about to make this explicit with min_t() to avoid type surprises?

> 
>  static u16 ice_get_txq_count(struct ice_pf *pf)
>  {
> -	return min(ice_get_avail_txq_count(pf), num_online_cpus());
> +	return min(ice_get_avail_txq_count(pf),
> +		   netif_get_num_default_rss_queues());
>  }

Same min_t() ?

Otherwise, fine for me.

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>

Re: [Intel-wired-lan] [PATCH iwl-next v2] ice: use netif_get_num_default_rss_queues()

[Michal Swiatkowski]

On Tue, Oct 28, 2025 at 07:48:11AM +0000, Loktionov, Aleksandr wrote:
> 
> 
> > -----Original Message-----
> > From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf
> > Of Michal Swiatkowski
> > Sent: Tuesday, October 28, 2025 8:07 AM
> > To: intel-wired-lan@lists.osuosl.org
> > Cc: netdev@vger.kernel.org; pmenzel@molgen.mpg.de; Lobakin, Aleksander
> > <aleksander.lobakin@intel.com>; Kitszel, Przemyslaw
> > <przemyslaw.kitszel@intel.com>; Keller, Jacob E
> > <jacob.e.keller@intel.com>; Michal Swiatkowski
> > <michal.swiatkowski@linux.intel.com>
> > Subject: [Intel-wired-lan] [PATCH iwl-next v2] ice: use
> > netif_get_num_default_rss_queues()
> > 
> > On some high-core systems (like AMD EPYC Bergamo, Intel Clearwater
> > Forest) 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 half
> > num_cpus(). Limit the default value to it using generic
> > netif_get_num_default_rss_queues().
> > 
> > Still, using ethtool the number of queues can be changed up to
> > num_online_cpus(). It can be done by calling:
> > $ethtool -L ethX combined max_cpu
> > 
> It could be nice to use $(nproc)?
>  $ ethtool -L ethX combined $(nproc)

Will change

> 
> > This change affects only the default queue amount.
> > 
> > Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
> > ---
> > v1 --> v2:
> >  * Follow Olek's comment and switch from custom limiting to the
> > generic
> >    netif_...() function.
> >  * Add more info in commit message (Paul)
> >  * Dropping RB tags, as it is different patch now
> > ---
> >  drivers/net/ethernet/intel/ice/ice_irq.c |  5 +++--
> >  drivers/net/ethernet/intel/ice/ice_lib.c | 12 ++++++++----
> >  2 files changed, 11 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/intel/ice/ice_irq.c
> > b/drivers/net/ethernet/intel/ice/ice_irq.c
> > index 30801fd375f0..1d9b2d646474 100644
> > --- a/drivers/net/ethernet/intel/ice/ice_irq.c
> > +++ b/drivers/net/ethernet/intel/ice/ice_irq.c
> > @@ -106,9 +106,10 @@ static struct ice_irq_entry
> > *ice_get_irq_res(struct ice_pf *pf,
> >  #define ICE_RDMA_AEQ_MSIX 1
> >  static int ice_get_default_msix_amount(struct ice_pf *pf)
> >  {
> > -	return ICE_MIN_LAN_OICR_MSIX + num_online_cpus() +
> > +	return ICE_MIN_LAN_OICR_MSIX +
> > netif_get_num_default_rss_queues() +
> >  	       (test_bit(ICE_FLAG_FD_ENA, pf->flags) ? ICE_FDIR_MSIX :
> > 0) +
> > -	       (ice_is_rdma_ena(pf) ? num_online_cpus() +
> > ICE_RDMA_AEQ_MSIX : 0);
> > +	       (ice_is_rdma_ena(pf) ?
> > netif_get_num_default_rss_queues() +
> > +				      ICE_RDMA_AEQ_MSIX : 0);
> >  }
> > 
> >  /**
> > diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c
> > b/drivers/net/ethernet/intel/ice/ice_lib.c
> > index bac481e8140d..e366d089bef9 100644
> > --- a/drivers/net/ethernet/intel/ice/ice_lib.c
> > +++ b/drivers/net/ethernet/intel/ice/ice_lib.c
> > @@ -159,12 +159,14 @@ static void ice_vsi_set_num_desc(struct ice_vsi
> > *vsi)
> > 
> >  static u16 ice_get_rxq_count(struct ice_pf *pf)
> >  {
> > -	return min(ice_get_avail_rxq_count(pf), num_online_cpus());
> > +	return min(ice_get_avail_rxq_count(pf),
> > +		   netif_get_num_default_rss_queues());
> >  }
> min(a, b) resolves to the type of the expression, which here will be int due to netif_get_num_default_rss_queues() returning int. 
> That implicitly truncates to u16 on return.
> What do you think about to make this explicit with min_t() to avoid type surprises?

We will just hide the truncing in the min_t() call. Probably if we
assuming that cpu / 2 can be higher than U16_MAX we should check that
here. Is it needed? (Previous situation is the same, num_online_cpus() is
returning int).

> 
> > 
> >  static u16 ice_get_txq_count(struct ice_pf *pf)
> >  {
> > -	return min(ice_get_avail_txq_count(pf), num_online_cpus());
> > +	return min(ice_get_avail_txq_count(pf),
> > +		   netif_get_num_default_rss_queues());
> >  }
> 
> Same min_t() ?
> 
> Otherwise, fine for me.

Thanks

> 
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>