| Message ID | 1340624745-8650-12-git-send-email-yuvalmin@broadcom.com |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
> -----Original Message----- > From: netdev-owner@vger.kernel.org [mailto:netdev- > owner@vger.kernel.org] On Behalf Of Yuval Mintz > Sent: Monday, June 25, 2012 4:46 AM > To: davem@davemloft.net; netdev@vger.kernel.org > Cc: eilong@broadcom.com; Yuval Mintz; Kirsher, Jeffrey T > Subject: [RFC net-next (v2) 11/14] igb: set maximal number of default > RSS queues > > Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com> > Signed-off-by: Eilon Greenstein <eilong@broadcom.com> > > Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com> > --- > drivers/net/ethernet/intel/igb/igb_main.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/drivers/net/ethernet/intel/igb/igb_main.c > b/drivers/net/ethernet/intel/igb/igb_main.c > index 01ced68..b11ee60 100644 > --- a/drivers/net/ethernet/intel/igb/igb_main.c > +++ b/drivers/net/ethernet/intel/igb/igb_main.c > @@ -2465,7 +2465,8 @@ static int __devinit igb_sw_init(struct > igb_adapter *adapter) > break; > } > > - adapter->rss_queues = min_t(u32, max_rss_queues, > num_online_cpus()); > + adapter->rss_queues = min_t(u32, max_rss_queues, > + netif_get_num_default_rss_queues()); > > /* Determine if we need to pair queues. */ > switch (hw->mac.type) { > -- > 1.7.9.rc2 Since igb supports a maximum of 8 RSS queues anyway, it's generally unaffected by this change. That being said, I'm confused about what you're trying to accomplish--is it to standardize the number of RSS queues or limit the number of interrupts by default? Or is it the former with a hope that it will trickle down to the latter? For example, if you take an igb device that supports 8 RSS queues (say, I350) and you change the default to 4 RSS queues, you will end up with the same number of interrupt vectors being requested as we will disable queue pairing and request separate vectors for Rx/Tx queues. I haven't looked at the other drivers affected by this RFC, but it's possible other drivers behave the same way. Matthew Matthew Vick Linux Development LAN Access Division Intel Corporation -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, 2012-06-25 at 17:31 +0000, Vick, Matthew wrote: > > -----Original Message----- > > From: netdev-owner@vger.kernel.org [mailto:netdev- > > owner@vger.kernel.org] On Behalf Of Yuval Mintz > > Sent: Monday, June 25, 2012 4:46 AM > > To: davem@davemloft.net; netdev@vger.kernel.org > > Cc: eilong@broadcom.com; Yuval Mintz; Kirsher, Jeffrey T > > Subject: [RFC net-next (v2) 11/14] igb: set maximal number of default > > RSS queues > > > > Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com> > > Signed-off-by: Eilon Greenstein <eilong@broadcom.com> > > > > Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com> > > --- > > drivers/net/ethernet/intel/igb/igb_main.c | 3 ++- > > 1 files changed, 2 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/net/ethernet/intel/igb/igb_main.c > > b/drivers/net/ethernet/intel/igb/igb_main.c > > index 01ced68..b11ee60 100644 > > --- a/drivers/net/ethernet/intel/igb/igb_main.c > > +++ b/drivers/net/ethernet/intel/igb/igb_main.c > > @@ -2465,7 +2465,8 @@ static int __devinit igb_sw_init(struct > > igb_adapter *adapter) > > break; > > } > > > > - adapter->rss_queues = min_t(u32, max_rss_queues, > > num_online_cpus()); > > + adapter->rss_queues = min_t(u32, max_rss_queues, > > + netif_get_num_default_rss_queues()); > > > > /* Determine if we need to pair queues. */ > > switch (hw->mac.type) { > > -- > > 1.7.9.rc2 > > Since igb supports a maximum of 8 RSS queues anyway, it's generally unaffected by this change. That being said, I'm confused about what you're trying to accomplish--is it to standardize the number of RSS queues or limit the number of interrupts by default? Or is it the former with a hope that it will trickle down to the latter? > > For example, if you take an igb device that supports 8 RSS queues (say, I350) and you change the default to 4 RSS queues, you will end up with the same number of interrupt vectors being requested as we will disable queue pairing and request separate vectors for Rx/Tx queues. I haven't looked at the other drivers affected by this RFC, but it's possible other drivers behave the same way. The main motivation is the Rx rings that consume significant amount of memory. The MSI-X vectors are a nice byproduct, but the logic you describe still sounds good for this kind of low numbers. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, 2012-06-25 at 17:31 +0000, Vick, Matthew wrote: > > -----Original Message----- > > From: netdev-owner@vger.kernel.org [mailto:netdev- > > owner@vger.kernel.org] On Behalf Of Yuval Mintz > > Sent: Monday, June 25, 2012 4:46 AM > > To: davem@davemloft.net; netdev@vger.kernel.org > > Cc: eilong@broadcom.com; Yuval Mintz; Kirsher, Jeffrey T > > Subject: [RFC net-next (v2) 11/14] igb: set maximal number of default > > RSS queues > > > > Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com> > > Signed-off-by: Eilon Greenstein <eilong@broadcom.com> > > > > Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com> > > --- > > drivers/net/ethernet/intel/igb/igb_main.c | 3 ++- > > 1 files changed, 2 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/net/ethernet/intel/igb/igb_main.c > > b/drivers/net/ethernet/intel/igb/igb_main.c > > index 01ced68..b11ee60 100644 > > --- a/drivers/net/ethernet/intel/igb/igb_main.c > > +++ b/drivers/net/ethernet/intel/igb/igb_main.c > > @@ -2465,7 +2465,8 @@ static int __devinit igb_sw_init(struct > > igb_adapter *adapter) > > break; > > } > > > > - adapter->rss_queues = min_t(u32, max_rss_queues, > > num_online_cpus()); > > + adapter->rss_queues = min_t(u32, max_rss_queues, > > + netif_get_num_default_rss_queues()); > > > > /* Determine if we need to pair queues. */ > > switch (hw->mac.type) { > > -- > > 1.7.9.rc2 > > Since igb supports a maximum of 8 RSS queues anyway, it's generally > unaffected by this change. I'm interested in providing a global configuration mechanism for this, which is why I asked Yuval to introduce this function. > That being said, I'm confused about what you're trying to > accomplish--is it to standardize the number of RSS queues or limit the > number of interrupts by default? Or is it the former with a hope that > it will trickle down to the latter? > > For example, if you take an igb device that supports 8 RSS queues > (say, I350) and you change the default to 4 RSS queues, you will end > up with the same number of interrupt vectors being requested as we > will disable queue pairing and request separate vectors for Rx/Tx > queues. I haven't looked at the other drivers affected by this RFC, > but it's possible other drivers behave the same way. sfc also supports those two modes, but under control of a module parameter. If it's a common enough feature then perhaps it should also be subject to global configuration (though that might be confusing if most drivers continue to support only one mode). Ben.
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index 01ced68..b11ee60 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -2465,7 +2465,8 @@ static int __devinit igb_sw_init(struct igb_adapter *adapter) break; } - adapter->rss_queues = min_t(u32, max_rss_queues, num_online_cpus()); + adapter->rss_queues = min_t(u32, max_rss_queues, + netif_get_num_default_rss_queues()); /* Determine if we need to pair queues. */ switch (hw->mac.type) {