| Message ID | 1340118848-30978-6-git-send-email-yuvalmin@broadcom.com |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
On 06/19/2012 08:13 AM, Yuval Mintz wrote: > 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/ixgbevf/ixgbevf_main.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c > index f69ec42..3ad46c2 100644 > --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c > +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c > @@ -2014,7 +2014,7 @@ err_tx_ring_allocation: > static int ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) > { > int err = 0; > - int vector, v_budget; > + int vector, v_budget, ncpu; > > /* > * It's easy to be greedy for MSI-X vectors, but it really > @@ -2022,8 +2022,9 @@ static int ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) > * than CPU's. So let's be conservative and only ask for > * (roughly) twice the number of vectors as there are CPU's. > */ > + ncpu = min_t(int, num_online_cpus(), DEFAULT_MAX_NUM_RSS_QUEUES); > v_budget = min(adapter->num_rx_queues + adapter->num_tx_queues, > - (int)(num_online_cpus() * 2)) + NON_Q_VECTORS; > + ncpu * 2) + NON_Q_VECTORS; > > /* A failure in MSI-X entry allocation isn't fatal, but it does > * mean we disable MSI-X capabilities of the adapter. */ This change is pointless on the ixgbevf driver. The VF hardware can support at most 4 RSS queues. As such num_rx_queues + num_tx_queues will never exceed 8 so you are essentially adding a necessary min(x,8). Thanks, Alex -- 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 Tue, 2012-06-19 at 08:39 -0700, Alexander Duyck wrote: > On 06/19/2012 08:13 AM, Yuval Mintz wrote: > > 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/ixgbevf/ixgbevf_main.c | 5 +++-- > > 1 files changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c > > index f69ec42..3ad46c2 100644 > > --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c > > +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c > > @@ -2014,7 +2014,7 @@ err_tx_ring_allocation: > > static int ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) > > { > > int err = 0; > > - int vector, v_budget; > > + int vector, v_budget, ncpu; > > > > /* > > * It's easy to be greedy for MSI-X vectors, but it really > > @@ -2022,8 +2022,9 @@ static int ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) > > * than CPU's. So let's be conservative and only ask for > > * (roughly) twice the number of vectors as there are CPU's. > > */ > > + ncpu = min_t(int, num_online_cpus(), DEFAULT_MAX_NUM_RSS_QUEUES); > > v_budget = min(adapter->num_rx_queues + adapter->num_tx_queues, > > - (int)(num_online_cpus() * 2)) + NON_Q_VECTORS; > > + ncpu * 2) + NON_Q_VECTORS; > > > > /* A failure in MSI-X entry allocation isn't fatal, but it does > > * mean we disable MSI-X capabilities of the adapter. */ > This change is pointless on the ixgbevf driver. The VF hardware can > support at most 4 RSS queues. As such num_rx_queues + num_tx_queues > will never exceed 8 so you are essentially adding a necessary min(x,8). It is pointless with the current value, but if someone will edit the kernel source code and replace the 8 with a 2, it will become meaningful. The compiler will optimize this part, and I think that for completion, it is best to keep this reference so a future default number change will not be missed. Eilon -- 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 Tue, 19 Jun 2012 19:06:53 +0300 Eilon Greenstein <eilong@broadcom.com> wrote: > On Tue, 2012-06-19 at 08:39 -0700, Alexander Duyck wrote: > > On 06/19/2012 08:13 AM, Yuval Mintz wrote: > > > 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/ixgbevf/ixgbevf_main.c | 5 +++-- > > > 1 files changed, 3 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c > > > b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c index > > > f69ec42..3ad46c2 100644 --- > > > a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c +++ > > > b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c @@ -2014,7 > > > +2014,7 @@ err_tx_ring_allocation: static int > > > ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) > > > { int err = 0; > > > - int vector, v_budget; > > > + int vector, v_budget, ncpu; > > > > > > /* > > > * It's easy to be greedy for MSI-X vectors, but it > > > really @@ -2022,8 +2022,9 @@ static int > > > ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) > > > * than CPU's. So let's be conservative and only ask for > > > * (roughly) twice the number of vectors as there are > > > CPU's. */ > > > + ncpu = min_t(int, num_online_cpus(), > > > DEFAULT_MAX_NUM_RSS_QUEUES); v_budget = > > > min(adapter->num_rx_queues + adapter->num_tx_queues, > > > - (int)(num_online_cpus() * 2)) + > > > NON_Q_VECTORS; > > > + ncpu * 2) + NON_Q_VECTORS; > > > > > > /* A failure in MSI-X entry allocation isn't fatal, but > > > it does > > > * mean we disable MSI-X capabilities of the adapter. */ > > This change is pointless on the ixgbevf driver. The VF hardware can > > support at most 4 RSS queues. As such num_rx_queues + num_tx_queues > > will never exceed 8 so you are essentially adding a necessary > > min(x,8). > > It is pointless with the current value, but if someone will edit the > kernel source code and replace the 8 with a 2, it will become > meaningful. The compiler will optimize this part, and I think that for > completion, it is best to keep this reference so a future default > number change will not be missed. > > Eilon I don't feel there is any real point to making this change to the ixgbevf driver. 82599 virtual functions have 3 MSI-X vectors, one of which is for the mailbox and the other two can be shared with tx/rx queue pairs or assigned separately to tx or rx queues. So this code is pointless no matter what value is set for DEFAULT_MAX_NUM_RSS_QUEUES. Perhaps the patches to the other drivers in your RFC will have some effect but this one looks like a no-op for the ixgbevf driver so there is no reason for it. - Greg > > > -- > 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 -- 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 Tue, 2012-06-19 at 11:07 -0700, Greg Rose wrote: > On Tue, 19 Jun 2012 19:06:53 +0300 > Eilon Greenstein <eilong@broadcom.com> wrote: > > > On Tue, 2012-06-19 at 08:39 -0700, Alexander Duyck wrote: > > > On 06/19/2012 08:13 AM, Yuval Mintz wrote: > > > > 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/ixgbevf/ixgbevf_main.c | 5 +++-- > > > > 1 files changed, 3 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c > > > > b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c index > > > > f69ec42..3ad46c2 100644 --- > > > > a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c +++ > > > > b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c @@ -2014,7 > > > > +2014,7 @@ err_tx_ring_allocation: static int > > > > ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) > > > > { int err = 0; > > > > - int vector, v_budget; > > > > + int vector, v_budget, ncpu; > > > > > > > > /* > > > > * It's easy to be greedy for MSI-X vectors, but it > > > > really @@ -2022,8 +2022,9 @@ static int > > > > ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) > > > > * than CPU's. So let's be conservative and only ask for > > > > * (roughly) twice the number of vectors as there are > > > > CPU's. */ > > > > + ncpu = min_t(int, num_online_cpus(), > > > > DEFAULT_MAX_NUM_RSS_QUEUES); v_budget = > > > > min(adapter->num_rx_queues + adapter->num_tx_queues, > > > > - (int)(num_online_cpus() * 2)) + > > > > NON_Q_VECTORS; > > > > + ncpu * 2) + NON_Q_VECTORS; > > > > > > > > /* A failure in MSI-X entry allocation isn't fatal, but > > > > it does > > > > * mean we disable MSI-X capabilities of the adapter. */ > > > This change is pointless on the ixgbevf driver. The VF hardware can > > > support at most 4 RSS queues. As such num_rx_queues + num_tx_queues > > > will never exceed 8 so you are essentially adding a necessary > > > min(x,8). > > > > It is pointless with the current value, but if someone will edit the > > kernel source code and replace the 8 with a 2, it will become > > meaningful. The compiler will optimize this part, and I think that for > > completion, it is best to keep this reference so a future default > > number change will not be missed. > > > > Eilon > > I don't feel there is any real point to making this change to the > ixgbevf driver. 82599 virtual functions have 3 MSI-X vectors, one of > which is for the mailbox and the other two can be shared with tx/rx > queue pairs or assigned separately to tx or rx queues. So this code is > pointless no matter what value is set for DEFAULT_MAX_NUM_RSS_QUEUES. > Perhaps the patches to the other drivers in your RFC will have some > effect but this one looks like a no-op for the ixgbevf driver so there > is no reason for it. OK - I guess we can just add a comment in this location saying that using DEFAULT_MAX_NUM_RSS_QUEUES is meaningless for the ixgbevf with that explanation so it will not look as if it was simply over looked. Thanks, Eilon -- 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
>>>> * It's easy to be greedy for MSI-X vectors, but it >>>> really @@ -2022,8 +2022,9 @@ static int >>>> ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) >>>> * than CPU's. So let's be conservative and only ask for >>>> * (roughly) twice the number of vectors as there are >>>> CPU's. */ >>>> + ncpu = min_t(int, num_online_cpus(), >>>> DEFAULT_MAX_NUM_RSS_QUEUES); v_budget = >>>> min(adapter->num_rx_queues + adapter->num_tx_queues, >>>> - (int)(num_online_cpus() * 2)) + >>>> NON_Q_VECTORS; >>>> + ncpu * 2) + NON_Q_VECTORS; >>>> >>>> /* A failure in MSI-X entry allocation isn't fatal, but >>>> it does >>>> * mean we disable MSI-X capabilities of the adapter. */ >>> This change is pointless on the ixgbevf driver. The VF hardware can >>> support at most 4 RSS queues. As such num_rx_queues + num_tx_queues >>> will never exceed 8 so you are essentially adding a necessary >>> min(x,8). >> >> It is pointless with the current value, but if someone will edit the >> kernel source code and replace the 8 with a 2, it will become >> meaningful. The compiler will optimize this part, and I think that for >> completion, it is best to keep this reference so a future default >> number change will not be missed. >> >> Eilon > > I don't feel there is any real point to making this change to the > ixgbevf driver. 82599 virtual functions have 3 MSI-X vectors, one of > which is for the mailbox and the other two can be shared with tx/rx > queue pairs or assigned separately to tx or rx queues. So this code is > pointless no matter what value is set for DEFAULT_MAX_NUM_RSS_QUEUES. > Perhaps the patches to the other drivers in your RFC will have some > effect but this one looks like a no-op for the ixgbevf driver so there > is no reason for it. > > - Greg > Hi Greg, Since we're changing the RFC to use a new wrapper function which should replace num_online_cpus (for these purpose), the next RFC version will still change this driver (for uniformity, if nothing else). Of course, if you would still have reservations for this change - send them. Thanks, Yuval -- 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
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c index f69ec42..3ad46c2 100644 --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c @@ -2014,7 +2014,7 @@ err_tx_ring_allocation: static int ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) { int err = 0; - int vector, v_budget; + int vector, v_budget, ncpu; /* * It's easy to be greedy for MSI-X vectors, but it really @@ -2022,8 +2022,9 @@ static int ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) * than CPU's. So let's be conservative and only ask for * (roughly) twice the number of vectors as there are CPU's. */ + ncpu = min_t(int, num_online_cpus(), DEFAULT_MAX_NUM_RSS_QUEUES); v_budget = min(adapter->num_rx_queues + adapter->num_tx_queues, - (int)(num_online_cpus() * 2)) + NON_Q_VECTORS; + ncpu * 2) + NON_Q_VECTORS; /* A failure in MSI-X entry allocation isn't fatal, but it does * mean we disable MSI-X capabilities of the adapter. */