[PATCH 0/3] net: mana: add irq_spread()

[PATCH 0/3] net: mana: add irq_spread()

[Yury Norov]

Add irq_spread() function that makes the driver working 15% faster than
with cpumask_local_spread()

Yury Norov (3):
  cpumask: add cpumask_weight_andnot()
  cpumask: define cleanup function for cpumasks
  net: mana: add a function to spread IRQs per CPUs

 .../net/ethernet/microsoft/mana/gdma_main.c   | 28 +++++++++++++++++++
 include/linux/bitmap.h                        | 12 ++++++++
 include/linux/cpumask.h                       | 17 +++++++++++
 lib/bitmap.c                                  |  7 +++++
 4 files changed, 64 insertions(+)

-- 
2.40.1

[PATCH 1/3] cpumask: add cpumask_weight_andnot()

[Yury Norov]

Similarly to cpumask_weight_and(), cpumask_weight_andnot() is a handy
helper that may help to avoid creating an intermediate mask just to
calculate number of bits that set in a 1st given mask, and clear in 2nd
one.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
 include/linux/bitmap.h  | 12 ++++++++++++
 include/linux/cpumask.h | 13 +++++++++++++
 lib/bitmap.c            |  7 +++++++
 3 files changed, 32 insertions(+)

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 99451431e4d6..5814e9ee40ba 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -54,6 +54,7 @@ struct device;
  *  bitmap_full(src, nbits)                     Are all bits set in *src?
  *  bitmap_weight(src, nbits)                   Hamming Weight: number set bits
  *  bitmap_weight_and(src1, src2, nbits)        Hamming Weight of and'ed bitmap
+ *  bitmap_weight_andnot(src1, src2, nbits)     Hamming Weight of andnot'ed bitmap
  *  bitmap_set(dst, pos, nbits)                 Set specified bit area
  *  bitmap_clear(dst, pos, nbits)               Clear specified bit area
  *  bitmap_find_next_zero_area(buf, len, pos, n, mask)  Find bit free area
@@ -169,6 +170,8 @@ bool __bitmap_subset(const unsigned long *bitmap1,
 unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
 unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
 				 const unsigned long *bitmap2, unsigned int nbits);
+unsigned int __bitmap_weight_andnot(const unsigned long *bitmap1,
+				    const unsigned long *bitmap2, unsigned int nbits);
 void __bitmap_set(unsigned long *map, unsigned int start, int len);
 void __bitmap_clear(unsigned long *map, unsigned int start, int len);
 
@@ -425,6 +428,15 @@ unsigned long bitmap_weight_and(const unsigned long *src1,
 	return __bitmap_weight_and(src1, src2, nbits);
 }
 
+static __always_inline
+unsigned long bitmap_weight_andnot(const unsigned long *src1,
+				   const unsigned long *src2, unsigned int nbits)
+{
+	if (small_const_nbits(nbits))
+		return hweight_long(*src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits));
+	return __bitmap_weight_andnot(src1, src2, nbits);
+}
+
 static __always_inline void bitmap_set(unsigned long *map, unsigned int start,
 		unsigned int nbits)
 {
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index cfb545841a2c..228c23eb36d2 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -719,6 +719,19 @@ static inline unsigned int cpumask_weight_and(const struct cpumask *srcp1,
 	return bitmap_weight_and(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits);
 }
 
+/**
+ * cpumask_weight_andnot - Count of bits in (*srcp1 & ~*srcp2)
+ * @srcp1: the cpumask to count bits (< nr_cpu_ids) in.
+ * @srcp2: the cpumask to count bits (< nr_cpu_ids) in.
+ *
+ * Return: count of bits set in both *srcp1 and *srcp2
+ */
+static inline unsigned int cpumask_weight_andnot(const struct cpumask *srcp1,
+						const struct cpumask *srcp2)
+{
+	return bitmap_weight_andnot(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits);
+}
+
 /**
  * cpumask_shift_right - *dstp = *srcp >> n
  * @dstp: the cpumask result
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 09522af227f1..b97692854966 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -348,6 +348,13 @@ unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
 }
 EXPORT_SYMBOL(__bitmap_weight_and);
 
+unsigned int __bitmap_weight_andnot(const unsigned long *bitmap1,
+				const unsigned long *bitmap2, unsigned int bits)
+{
+	return BITMAP_WEIGHT(bitmap1[idx] & ~bitmap2[idx], bits);
+}
+EXPORT_SYMBOL(__bitmap_weight_andnot);
+
 void __bitmap_set(unsigned long *map, unsigned int start, int len)
 {
 	unsigned long *p = map + BIT_WORD(start);
-- 
2.40.1

[PATCH 2/3] cpumask: define cleanup function for cpumasks

[Yury Norov]

Now we can simplify code that allocates cpumasks for local needs.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
 include/linux/cpumask.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 228c23eb36d2..1c29947db848 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -7,6 +7,7 @@
  * set of CPUs in a system, one bit position per CPU number.  In general,
  * only nr_cpu_ids (<= NR_CPUS) bits are valid.
  */
+#include <linux/cleanup.h>
 #include <linux/kernel.h>
 #include <linux/threads.h>
 #include <linux/bitmap.h>
@@ -990,6 +991,8 @@ static inline bool cpumask_available(cpumask_var_t mask)
 }
 #endif /* CONFIG_CPUMASK_OFFSTACK */
 
+DEFINE_FREE(free_cpumask_var, struct cpumask *, if (_T) free_cpumask_var(_T));
+
 /* It's common to want to use cpu_all_mask in struct member initializers,
  * so it has to refer to an address rather than a pointer. */
 extern const DECLARE_BITMAP(cpu_all_bits, NR_CPUS);
-- 
2.40.1

[PATCH 3/3] net: mana: add a function to spread IRQs per CPUs

[Yury Norov]

Souradeep investigated that the driver performs faster if IRQs are
spread on CPUs with the following heuristics:

1. No more than one IRQ per CPU, if possible;
2. NUMA locality is the second priority;
3. Sibling dislocality is the last priority.

Let's consider this topology:

Node            0               1
Core        0       1       2       3
CPU       0   1   2   3   4   5   6   7

The most performant IRQ distribution based on the above topology
and heuristics may look like this:

IRQ     Nodes   Cores   CPUs
0       1       0       0-1
1       1       1       2-3
2       1       0       0-1
3       1       1       2-3
4       2       2       4-5
5       2       3       6-7
6       2       2       4-5
7       2       3       6-7

The irq_setup() routine introduced in this patch leverages the
for_each_numa_hop_mask() iterator and assigns IRQs to sibling groups
as described above.

According to [1], for NUMA-aware but sibling-ignorant IRQ distribution
based on cpumask_local_spread() performance test results look like this:

./ntttcp -r -m 16
NTTTCP for Linux 1.4.0
---------------------------------------------------------
08:05:20 INFO: 17 threads created
08:05:28 INFO: Network activity progressing...
08:06:28 INFO: Test run completed.
08:06:28 INFO: Test cycle finished.
08:06:28 INFO: #####  Totals:  #####
08:06:28 INFO: test duration    :60.00 seconds
08:06:28 INFO: total bytes      :630292053310
08:06:28 INFO:   throughput     :84.04Gbps
08:06:28 INFO:   retrans segs   :4
08:06:28 INFO: cpu cores        :192
08:06:28 INFO:   cpu speed      :3799.725MHz
08:06:28 INFO:   user           :0.05%
08:06:28 INFO:   system         :1.60%
08:06:28 INFO:   idle           :96.41%
08:06:28 INFO:   iowait         :0.00%
08:06:28 INFO:   softirq        :1.94%
08:06:28 INFO:   cycles/byte    :2.50
08:06:28 INFO: cpu busy (all)   :534.41%

For NUMA- and sibling-aware IRQ distribution, the same test works
15% faster:

./ntttcp -r -m 16
NTTTCP for Linux 1.4.0
---------------------------------------------------------
08:08:51 INFO: 17 threads created
08:08:56 INFO: Network activity progressing...
08:09:56 INFO: Test run completed.
08:09:56 INFO: Test cycle finished.
08:09:56 INFO: #####  Totals:  #####
08:09:56 INFO: test duration    :60.00 seconds
08:09:56 INFO: total bytes      :741966608384
08:09:56 INFO:   throughput     :98.93Gbps
08:09:56 INFO:   retrans segs   :6
08:09:56 INFO: cpu cores        :192
08:09:56 INFO:   cpu speed      :3799.791MHz
08:09:56 INFO:   user           :0.06%
08:09:56 INFO:   system         :1.81%
08:09:56 INFO:   idle           :96.18%
08:09:56 INFO:   iowait         :0.00%
08:09:56 INFO:   softirq        :1.95%
08:09:56 INFO:   cycles/byte    :2.25
08:09:56 INFO: cpu busy (all)   :569.22%

[1] https://lore.kernel.org/all/20231211063726.GA4977@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net/

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Co-developed-by: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
---
 .../net/ethernet/microsoft/mana/gdma_main.c   | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index 6367de0c2c2e..11e64e42e3b2 100644
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -1243,6 +1243,34 @@ void mana_gd_free_res_map(struct gdma_resource *r)
 	r->size = 0;
 }
 
+static __maybe_unused int irq_setup(unsigned int *irqs, unsigned int len, int node)
+{
+	const struct cpumask *next, *prev = cpu_none_mask;
+	cpumask_var_t cpus __free(free_cpumask_var);
+	int cpu, weight;
+
+	if (!alloc_cpumask_var(&cpus, GFP_KERNEL))
+		return -ENOMEM;
+
+	rcu_read_lock();
+	for_each_numa_hop_mask(next, node) {
+		weight = cpumask_weight_andnot(next, prev);
+		while (weight-- > 0) {
+			cpumask_andnot(cpus, next, prev);
+			for_each_cpu(cpu, cpus) {
+				if (len-- == 0)
+					goto done;
+				irq_set_affinity_and_hint(*irqs++, topology_sibling_cpumask(cpu));
+				cpumask_andnot(cpus, cpus, topology_sibling_cpumask(cpu));
+			}
+		}
+		prev = next;
+	}
+done:
+	rcu_read_unlock();
+	return 0;
+}
+
 static int mana_gd_setup_irqs(struct pci_dev *pdev)
 {
 	unsigned int max_queues_per_port = num_online_cpus();
-- 
2.40.1

Re: [PATCH 3/3] net: mana: add a function to spread IRQs per CPUs

[Jacob Keller]

On 12/17/2023 1:32 PM, Yury Norov wrote:
> +static __maybe_unused int irq_setup(unsigned int *irqs, unsigned int len, int node)
> +{
> +	const struct cpumask *next, *prev = cpu_none_mask;
> +	cpumask_var_t cpus __free(free_cpumask_var);
> +	int cpu, weight;
> +
> +	if (!alloc_cpumask_var(&cpus, GFP_KERNEL))
> +		return -ENOMEM;
> +
> +	rcu_read_lock();
> +	for_each_numa_hop_mask(next, node) {
> +		weight = cpumask_weight_andnot(next, prev);
> +		while (weight-- > 0) {
> +			cpumask_andnot(cpus, next, prev);
> +			for_each_cpu(cpu, cpus) {
> +				if (len-- == 0)
> +					goto done;
> +				irq_set_affinity_and_hint(*irqs++, topology_sibling_cpumask(cpu));
> +				cpumask_andnot(cpus, cpus, topology_sibling_cpumask(cpu));
> +			}
> +		}
> +		prev = next;
> +	}
> +done:
> +	rcu_read_unlock();
> +	return 0;
> +}
> +

You're adding a function here but its not called and even marked as
__maybe_unused?

>  static int mana_gd_setup_irqs(struct pci_dev *pdev)
>  {
>  	unsigned int max_queues_per_port = num_online_cpus();

Re: [PATCH 0/3] net: mana: add irq_spread()

[Jacob Keller]

On 12/17/2023 1:32 PM, Yury Norov wrote:
> Add irq_spread() function that makes the driver working 15% faster than
> with cpumask_local_spread()
> 
> Yury Norov (3):
>   cpumask: add cpumask_weight_andnot()
>   cpumask: define cleanup function for cpumasks
>   net: mana: add a function to spread IRQs per CPUs
> 
>  .../net/ethernet/microsoft/mana/gdma_main.c   | 28 +++++++++++++++++++
>  include/linux/bitmap.h                        | 12 ++++++++
>  include/linux/cpumask.h                       | 17 +++++++++++
>  lib/bitmap.c                                  |  7 +++++
>  4 files changed, 64 insertions(+)
> 

Process would be to tag this for which tree it aims for. Since this
looks like an improvement and includes cleanup and changes to add a new
helper function that makes me think it would be net-next.

Thanks,
Jake

Re: [PATCH 1/3] cpumask: add cpumask_weight_andnot()

[Jacob Keller]

On 12/17/2023 1:32 PM, Yury Norov wrote:
> Similarly to cpumask_weight_and(), cpumask_weight_andnot() is a handy
> helper that may help to avoid creating an intermediate mask just to
> calculate number of bits that set in a 1st given mask, and clear in 2nd
> one.
> 
> Signed-off-by: Yury Norov <yury.norov@gmail.com>

This seems reasonable to me.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>

> ---
>  include/linux/bitmap.h  | 12 ++++++++++++
>  include/linux/cpumask.h | 13 +++++++++++++
>  lib/bitmap.c            |  7 +++++++
>  3 files changed, 32 insertions(+)
> 
> diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
> index 99451431e4d6..5814e9ee40ba 100644
> --- a/include/linux/bitmap.h
> +++ b/include/linux/bitmap.h
> @@ -54,6 +54,7 @@ struct device;
>   *  bitmap_full(src, nbits)                     Are all bits set in *src?
>   *  bitmap_weight(src, nbits)                   Hamming Weight: number set bits
>   *  bitmap_weight_and(src1, src2, nbits)        Hamming Weight of and'ed bitmap
> + *  bitmap_weight_andnot(src1, src2, nbits)     Hamming Weight of andnot'ed bitmap
>   *  bitmap_set(dst, pos, nbits)                 Set specified bit area
>   *  bitmap_clear(dst, pos, nbits)               Clear specified bit area
>   *  bitmap_find_next_zero_area(buf, len, pos, n, mask)  Find bit free area
> @@ -169,6 +170,8 @@ bool __bitmap_subset(const unsigned long *bitmap1,
>  unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
>  unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
>  				 const unsigned long *bitmap2, unsigned int nbits);
> +unsigned int __bitmap_weight_andnot(const unsigned long *bitmap1,
> +				    const unsigned long *bitmap2, unsigned int nbits);
>  void __bitmap_set(unsigned long *map, unsigned int start, int len);
>  void __bitmap_clear(unsigned long *map, unsigned int start, int len);
>  
> @@ -425,6 +428,15 @@ unsigned long bitmap_weight_and(const unsigned long *src1,
>  	return __bitmap_weight_and(src1, src2, nbits);
>  }
>  
> +static __always_inline
> +unsigned long bitmap_weight_andnot(const unsigned long *src1,
> +				   const unsigned long *src2, unsigned int nbits)
> +{
> +	if (small_const_nbits(nbits))
> +		return hweight_long(*src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits));
> +	return __bitmap_weight_andnot(src1, src2, nbits);
> +}
> +
>  static __always_inline void bitmap_set(unsigned long *map, unsigned int start,
>  		unsigned int nbits)
>  {
> diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
> index cfb545841a2c..228c23eb36d2 100644
> --- a/include/linux/cpumask.h
> +++ b/include/linux/cpumask.h
> @@ -719,6 +719,19 @@ static inline unsigned int cpumask_weight_and(const struct cpumask *srcp1,
>  	return bitmap_weight_and(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits);
>  }
>  
> +/**
> + * cpumask_weight_andnot - Count of bits in (*srcp1 & ~*srcp2)
> + * @srcp1: the cpumask to count bits (< nr_cpu_ids) in.
> + * @srcp2: the cpumask to count bits (< nr_cpu_ids) in.
> + *
> + * Return: count of bits set in both *srcp1 and *srcp2
> + */
> +static inline unsigned int cpumask_weight_andnot(const struct cpumask *srcp1,
> +						const struct cpumask *srcp2)
> +{
> +	return bitmap_weight_andnot(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits);
> +}
> +
>  /**
>   * cpumask_shift_right - *dstp = *srcp >> n
>   * @dstp: the cpumask result
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 09522af227f1..b97692854966 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -348,6 +348,13 @@ unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
>  }
>  EXPORT_SYMBOL(__bitmap_weight_and);
>  
> +unsigned int __bitmap_weight_andnot(const unsigned long *bitmap1,
> +				const unsigned long *bitmap2, unsigned int bits)
> +{
> +	return BITMAP_WEIGHT(bitmap1[idx] & ~bitmap2[idx], bits);
> +}
> +EXPORT_SYMBOL(__bitmap_weight_andnot);
> +
>  void __bitmap_set(unsigned long *map, unsigned int start, int len)
>  {
>  	unsigned long *p = map + BIT_WORD(start);

Re: [PATCH 3/3] net: mana: add a function to spread IRQs per CPUs

[Yury Norov]

On Mon, Dec 18, 2023 at 01:17:53PM -0800, Jacob Keller wrote:
> 
> 
> On 12/17/2023 1:32 PM, Yury Norov wrote:
> > +static __maybe_unused int irq_setup(unsigned int *irqs, unsigned int len, int node)
> > +{
> > +	const struct cpumask *next, *prev = cpu_none_mask;
> > +	cpumask_var_t cpus __free(free_cpumask_var);
> > +	int cpu, weight;
> > +
> > +	if (!alloc_cpumask_var(&cpus, GFP_KERNEL))
> > +		return -ENOMEM;
> > +
> > +	rcu_read_lock();
> > +	for_each_numa_hop_mask(next, node) {
> > +		weight = cpumask_weight_andnot(next, prev);
> > +		while (weight-- > 0) {
> > +			cpumask_andnot(cpus, next, prev);
> > +			for_each_cpu(cpu, cpus) {
> > +				if (len-- == 0)
> > +					goto done;
> > +				irq_set_affinity_and_hint(*irqs++, topology_sibling_cpumask(cpu));
> > +				cpumask_andnot(cpus, cpus, topology_sibling_cpumask(cpu));
> > +			}
> > +		}
> > +		prev = next;
> > +	}
> > +done:
> > +	rcu_read_unlock();
> > +	return 0;
> > +}
> > +
> 
> You're adding a function here but its not called and even marked as
> __maybe_unused?

I expect that Souradeep would build his driver improvement on top of
this function. cpumask API is somewhat tricky to use it properly here,
so this is an attempt help him, instead of moving back and forth on
review.

Sorry, I had to be more explicit.

Thanks,
Yury

RE: [EXTERNAL] [PATCH 3/3] net: mana: add a function to spread IRQs per CPUs

[Souradeep Chakrabarti]

>-----Original Message-----
>From: Yury Norov <yury.norov@gmail.com>
>Sent: Monday, December 18, 2023 3:02 AM
>To: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>; KY Srinivasan
><kys@microsoft.com>; Haiyang Zhang <haiyangz@microsoft.com>;
>wei.liu@kernel.org; Dexuan Cui <decui@microsoft.com>; davem@davemloft.net;
>edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; Long Li
><longli@microsoft.com>; yury.norov@gmail.com; leon@kernel.org;
>cai.huoqing@linux.dev; ssengar@linux.microsoft.com; vkuznets@redhat.com;
>tglx@linutronix.de; linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; linux-
>kernel@vger.kernel.org; linux-rdma@vger.kernel.org
>Cc: Souradeep Chakrabarti <schakrabarti@microsoft.com>; Paul Rosswurm
><paulros@microsoft.com>
>Subject: [EXTERNAL] [PATCH 3/3] net: mana: add a function to spread IRQs per
>CPUs
>
>[Some people who received this message don't often get email from
>yury.norov@gmail.com. Learn why this is important at
>https://aka.ms/LearnAboutSenderIdentification ]
>
>Souradeep investigated that the driver performs faster if IRQs are spread on CPUs
>with the following heuristics:
>
>1. No more than one IRQ per CPU, if possible; 2. NUMA locality is the second
>priority; 3. Sibling dislocality is the last priority.
>
>Let's consider this topology:
>
>Node            0               1
>Core        0       1       2       3
>CPU       0   1   2   3   4   5   6   7
>
>The most performant IRQ distribution based on the above topology and heuristics
>may look like this:
>
>IRQ     Nodes   Cores   CPUs
>0       1       0       0-1
>1       1       1       2-3
>2       1       0       0-1
>3       1       1       2-3
>4       2       2       4-5
>5       2       3       6-7
>6       2       2       4-5
>7       2       3       6-7
>
>The irq_setup() routine introduced in this patch leverages the
>for_each_numa_hop_mask() iterator and assigns IRQs to sibling groups as
>described above.
>
>According to [1], for NUMA-aware but sibling-ignorant IRQ distribution based on
>cpumask_local_spread() performance test results look like this:
>
>./ntttcp -r -m 16
>NTTTCP for Linux 1.4.0
>---------------------------------------------------------
>08:05:20 INFO: 17 threads created
>08:05:28 INFO: Network activity progressing...
>08:06:28 INFO: Test run completed.
>08:06:28 INFO: Test cycle finished.
>08:06:28 INFO: #####  Totals:  #####
>08:06:28 INFO: test duration    :60.00 seconds
>08:06:28 INFO: total bytes      :630292053310
>08:06:28 INFO:   throughput     :84.04Gbps
>08:06:28 INFO:   retrans segs   :4
>08:06:28 INFO: cpu cores        :192
>08:06:28 INFO:   cpu speed      :3799.725MHz
>08:06:28 INFO:   user           :0.05%
>08:06:28 INFO:   system         :1.60%
>08:06:28 INFO:   idle           :96.41%
>08:06:28 INFO:   iowait         :0.00%
>08:06:28 INFO:   softirq        :1.94%
>08:06:28 INFO:   cycles/byte    :2.50
>08:06:28 INFO: cpu busy (all)   :534.41%
>
>For NUMA- and sibling-aware IRQ distribution, the same test works 15% faster:
>
>./ntttcp -r -m 16
>NTTTCP for Linux 1.4.0
>---------------------------------------------------------
>08:08:51 INFO: 17 threads created
>08:08:56 INFO: Network activity progressing...
>08:09:56 INFO: Test run completed.
>08:09:56 INFO: Test cycle finished.
>08:09:56 INFO: #####  Totals:  #####
>08:09:56 INFO: test duration    :60.00 seconds
>08:09:56 INFO: total bytes      :741966608384
>08:09:56 INFO:   throughput     :98.93Gbps
>08:09:56 INFO:   retrans segs   :6
>08:09:56 INFO: cpu cores        :192
>08:09:56 INFO:   cpu speed      :3799.791MHz
>08:09:56 INFO:   user           :0.06%
>08:09:56 INFO:   system         :1.81%
>08:09:56 INFO:   idle           :96.18%
>08:09:56 INFO:   iowait         :0.00%
>08:09:56 INFO:   softirq        :1.95%
>08:09:56 INFO:   cycles/byte    :2.25
>08:09:56 INFO: cpu busy (all)   :569.22%
>
>[1]
>https://lore.kernel/
>.org%2Fall%2F20231211063726.GA4977%40linuxonhyperv3.guj3yctzbm1etfxqx2v
>ob5hsef.xx.internal.cloudapp.net%2F&data=05%7C02%7Cschakrabarti%40micros
>oft.com%7Ca385a5a5d661458219c208dbff47a7ab%7C72f988bf86f141af91ab2d7
>cd011db47%7C1%7C0%7C638384455520036393%7CUnknown%7CTWFpbGZsb3d
>8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%
>7C3000%7C%7C%7C&sdata=kzoalzSu6frB0GIaUM5VWsz04%2FsB%2FBdXwXKb26
>IhqkE%3D&reserved=0
>
>Signed-off-by: Yury Norov <yury.norov@gmail.com>
>Co-developed-by: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
Please also add Signed-off-by: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
>---
> .../net/ethernet/microsoft/mana/gdma_main.c   | 28 +++++++++++++++++++
> 1 file changed, 28 insertions(+)
>
>diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c
>b/drivers/net/ethernet/microsoft/mana/gdma_main.c
>index 6367de0c2c2e..11e64e42e3b2 100644
>--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
>+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
>@@ -1243,6 +1243,34 @@ void mana_gd_free_res_map(struct gdma_resource
>*r)
>        r->size = 0;
> }
>
>+static __maybe_unused int irq_setup(unsigned int *irqs, unsigned int
>+len, int node) {
>+       const struct cpumask *next, *prev = cpu_none_mask;
>+       cpumask_var_t cpus __free(free_cpumask_var);
>+       int cpu, weight;
>+
>+       if (!alloc_cpumask_var(&cpus, GFP_KERNEL))
>+               return -ENOMEM;
>+
>+       rcu_read_lock();
>+       for_each_numa_hop_mask(next, node) {
>+               weight = cpumask_weight_andnot(next, prev);
>+               while (weight-- > 0) {
>+                       cpumask_andnot(cpus, next, prev);
>+                       for_each_cpu(cpu, cpus) {
>+                               if (len-- == 0)
>+                                       goto done;
>+                               irq_set_affinity_and_hint(*irqs++,
>topology_sibling_cpumask(cpu));
>+                               cpumask_andnot(cpus, cpus, topology_sibling_cpumask(cpu));
>+                       }
>+               }
>+               prev = next;
>+       }
>+done:
>+       rcu_read_unlock();
>+       return 0;
>+}
>+
> static int mana_gd_setup_irqs(struct pci_dev *pdev)  {
>        unsigned int max_queues_per_port = num_online_cpus();
>--
>2.40.1

RE: [EXTERNAL] [PATCH 3/3] net: mana: add a function to spread IRQs per CPUs

[Souradeep Chakrabarti]

>-----Original Message-----
>From: Yury Norov <yury.norov@gmail.com>
>Sent: Monday, December 18, 2023 3:02 AM
>To: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>; KY Srinivasan
><kys@microsoft.com>; Haiyang Zhang <haiyangz@microsoft.com>;
>wei.liu@kernel.org; Dexuan Cui <decui@microsoft.com>; davem@davemloft.net;
>edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; Long Li
><longli@microsoft.com>; yury.norov@gmail.com; leon@kernel.org;
>cai.huoqing@linux.dev; ssengar@linux.microsoft.com; vkuznets@redhat.com;
>tglx@linutronix.de; linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; linux-
>kernel@vger.kernel.org; linux-rdma@vger.kernel.org
>Cc: Souradeep Chakrabarti <schakrabarti@microsoft.com>; Paul Rosswurm
><paulros@microsoft.com>
>Subject: [EXTERNAL] [PATCH 3/3] net: mana: add a function to spread IRQs per
>CPUs
>
>[Some people who received this message don't often get email from
>yury.norov@gmail.com. Learn why this is important at
>https://aka.ms/LearnAboutSenderIdentification ]
>
>Souradeep investigated that the driver performs faster if IRQs are spread on CPUs
>with the following heuristics:
>
>1. No more than one IRQ per CPU, if possible; 2. NUMA locality is the second
>priority; 3. Sibling dislocality is the last priority.
>
>Let's consider this topology:
>
>Node            0               1
>Core        0       1       2       3
>CPU       0   1   2   3   4   5   6   7
>
>The most performant IRQ distribution based on the above topology and heuristics
>may look like this:
>
>IRQ     Nodes   Cores   CPUs
>0       1       0       0-1
>1       1       1       2-3
>2       1       0       0-1
>3       1       1       2-3
>4       2       2       4-5
>5       2       3       6-7
>6       2       2       4-5
>7       2       3       6-7
>
>The irq_setup() routine introduced in this patch leverages the
>for_each_numa_hop_mask() iterator and assigns IRQs to sibling groups as
>described above.
>
>According to [1], for NUMA-aware but sibling-ignorant IRQ distribution based on
>cpumask_local_spread() performance test results look like this:
>
>./ntttcp -r -m 16
>NTTTCP for Linux 1.4.0
>---------------------------------------------------------
>08:05:20 INFO: 17 threads created
>08:05:28 INFO: Network activity progressing...
>08:06:28 INFO: Test run completed.
>08:06:28 INFO: Test cycle finished.
>08:06:28 INFO: #####  Totals:  #####
>08:06:28 INFO: test duration    :60.00 seconds
>08:06:28 INFO: total bytes      :630292053310
>08:06:28 INFO:   throughput     :84.04Gbps
>08:06:28 INFO:   retrans segs   :4
>08:06:28 INFO: cpu cores        :192
>08:06:28 INFO:   cpu speed      :3799.725MHz
>08:06:28 INFO:   user           :0.05%
>08:06:28 INFO:   system         :1.60%
>08:06:28 INFO:   idle           :96.41%
>08:06:28 INFO:   iowait         :0.00%
>08:06:28 INFO:   softirq        :1.94%
>08:06:28 INFO:   cycles/byte    :2.50
>08:06:28 INFO: cpu busy (all)   :534.41%
>
>For NUMA- and sibling-aware IRQ distribution, the same test works 15% faster:
>
>./ntttcp -r -m 16
>NTTTCP for Linux 1.4.0
>---------------------------------------------------------
>08:08:51 INFO: 17 threads created
>08:08:56 INFO: Network activity progressing...
>08:09:56 INFO: Test run completed.
>08:09:56 INFO: Test cycle finished.
>08:09:56 INFO: #####  Totals:  #####
>08:09:56 INFO: test duration    :60.00 seconds
>08:09:56 INFO: total bytes      :741966608384
>08:09:56 INFO:   throughput     :98.93Gbps
>08:09:56 INFO:   retrans segs   :6
>08:09:56 INFO: cpu cores        :192
>08:09:56 INFO:   cpu speed      :3799.791MHz
>08:09:56 INFO:   user           :0.06%
>08:09:56 INFO:   system         :1.81%
>08:09:56 INFO:   idle           :96.18%
>08:09:56 INFO:   iowait         :0.00%
>08:09:56 INFO:   softirq        :1.95%
>08:09:56 INFO:   cycles/byte    :2.25
>08:09:56 INFO: cpu busy (all)   :569.22%
>
>[1]
>https://lore.kernel/
>.org%2Fall%2F20231211063726.GA4977%40linuxonhyperv3.guj3yctzbm1etfxqx2v
>ob5hsef.xx.internal.cloudapp.net%2F&data=05%7C02%7Cschakrabarti%40micros
>oft.com%7Ca385a5a5d661458219c208dbff47a7ab%7C72f988bf86f141af91ab2d7
>cd011db47%7C1%7C0%7C638384455520036393%7CUnknown%7CTWFpbGZsb3d
>8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%
>7C3000%7C%7C%7C&sdata=kzoalzSu6frB0GIaUM5VWsz04%2FsB%2FBdXwXKb26
>IhqkE%3D&reserved=0
>
>Signed-off-by: Yury Norov <yury.norov@gmail.com>
>Co-developed-by: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
>---
> .../net/ethernet/microsoft/mana/gdma_main.c   | 28 +++++++++++++++++++
> 1 file changed, 28 insertions(+)
>
>diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c
>b/drivers/net/ethernet/microsoft/mana/gdma_main.c
>index 6367de0c2c2e..11e64e42e3b2 100644
>--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
>+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
>@@ -1243,6 +1243,34 @@ void mana_gd_free_res_map(struct gdma_resource
>*r)
>        r->size = 0;
> }
>
>+static __maybe_unused int irq_setup(unsigned int *irqs, unsigned int
>+len, int node) {
>+       const struct cpumask *next, *prev = cpu_none_mask;
>+       cpumask_var_t cpus __free(free_cpumask_var);
>+       int cpu, weight;
>+
>+       if (!alloc_cpumask_var(&cpus, GFP_KERNEL))
>+               return -ENOMEM;
>+
>+       rcu_read_lock();
>+       for_each_numa_hop_mask(next, node) {
>+               weight = cpumask_weight_andnot(next, prev);
>+               while (weight-- > 0) {
Make it while (weight > 0) {
>+                       cpumask_andnot(cpus, next, prev);
>+                       for_each_cpu(cpu, cpus) {
>+                               if (len-- == 0)
>+                                       goto done;
>+                               irq_set_affinity_and_hint(*irqs++,
>topology_sibling_cpumask(cpu));
>+                               cpumask_andnot(cpus, cpus, topology_sibling_cpumask(cpu));
Here do --weight, else this code will traverse the same node N^2 times, where each
node has N cpus .
>+                       }
>+               }
>+               prev = next;
>+       }
>+done:
>+       rcu_read_unlock();
>+       return 0;
>+}
>+
> static int mana_gd_setup_irqs(struct pci_dev *pdev)  {
>        unsigned int max_queues_per_port = num_online_cpus();
>--
>2.40.1

Re: [EXTERNAL] [PATCH 3/3] net: mana: add a function to spread IRQs per CPUs

[Yury Norov]

On Tue, Dec 19, 2023 at 10:18:49AM +0000, Souradeep Chakrabarti wrote:
> 
> 
> >-----Original Message-----
> >From: Yury Norov <yury.norov@gmail.com>
> >Sent: Monday, December 18, 2023 3:02 AM
> >To: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>; KY Srinivasan
> ><kys@microsoft.com>; Haiyang Zhang <haiyangz@microsoft.com>;
> >wei.liu@kernel.org; Dexuan Cui <decui@microsoft.com>; davem@davemloft.net;
> >edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; Long Li
> ><longli@microsoft.com>; yury.norov@gmail.com; leon@kernel.org;
> >cai.huoqing@linux.dev; ssengar@linux.microsoft.com; vkuznets@redhat.com;
> >tglx@linutronix.de; linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; linux-
> >kernel@vger.kernel.org; linux-rdma@vger.kernel.org
> >Cc: Souradeep Chakrabarti <schakrabarti@microsoft.com>; Paul Rosswurm
> ><paulros@microsoft.com>
> >Subject: [EXTERNAL] [PATCH 3/3] net: mana: add a function to spread IRQs per
> >CPUs
> >
> >[Some people who received this message don't often get email from
> >yury.norov@gmail.com. Learn why this is important at
> >https://aka.ms/LearnAboutSenderIdentification ]
> >
> >Souradeep investigated that the driver performs faster if IRQs are spread on CPUs
> >with the following heuristics:
> >
> >1. No more than one IRQ per CPU, if possible; 2. NUMA locality is the second
> >priority; 3. Sibling dislocality is the last priority.
> >
> >Let's consider this topology:
> >
> >Node            0               1
> >Core        0       1       2       3
> >CPU       0   1   2   3   4   5   6   7
> >
> >The most performant IRQ distribution based on the above topology and heuristics
> >may look like this:
> >
> >IRQ     Nodes   Cores   CPUs
> >0       1       0       0-1
> >1       1       1       2-3
> >2       1       0       0-1
> >3       1       1       2-3
> >4       2       2       4-5
> >5       2       3       6-7
> >6       2       2       4-5
> >7       2       3       6-7
> >
> >The irq_setup() routine introduced in this patch leverages the
> >for_each_numa_hop_mask() iterator and assigns IRQs to sibling groups as
> >described above.
> >
> >According to [1], for NUMA-aware but sibling-ignorant IRQ distribution based on
> >cpumask_local_spread() performance test results look like this:
> >
> >./ntttcp -r -m 16
> >NTTTCP for Linux 1.4.0
> >---------------------------------------------------------
> >08:05:20 INFO: 17 threads created
> >08:05:28 INFO: Network activity progressing...
> >08:06:28 INFO: Test run completed.
> >08:06:28 INFO: Test cycle finished.
> >08:06:28 INFO: #####  Totals:  #####
> >08:06:28 INFO: test duration    :60.00 seconds
> >08:06:28 INFO: total bytes      :630292053310
> >08:06:28 INFO:   throughput     :84.04Gbps
> >08:06:28 INFO:   retrans segs   :4
> >08:06:28 INFO: cpu cores        :192
> >08:06:28 INFO:   cpu speed      :3799.725MHz
> >08:06:28 INFO:   user           :0.05%
> >08:06:28 INFO:   system         :1.60%
> >08:06:28 INFO:   idle           :96.41%
> >08:06:28 INFO:   iowait         :0.00%
> >08:06:28 INFO:   softirq        :1.94%
> >08:06:28 INFO:   cycles/byte    :2.50
> >08:06:28 INFO: cpu busy (all)   :534.41%
> >
> >For NUMA- and sibling-aware IRQ distribution, the same test works 15% faster:
> >
> >./ntttcp -r -m 16
> >NTTTCP for Linux 1.4.0
> >---------------------------------------------------------
> >08:08:51 INFO: 17 threads created
> >08:08:56 INFO: Network activity progressing...
> >08:09:56 INFO: Test run completed.
> >08:09:56 INFO: Test cycle finished.
> >08:09:56 INFO: #####  Totals:  #####
> >08:09:56 INFO: test duration    :60.00 seconds
> >08:09:56 INFO: total bytes      :741966608384
> >08:09:56 INFO:   throughput     :98.93Gbps
> >08:09:56 INFO:   retrans segs   :6
> >08:09:56 INFO: cpu cores        :192
> >08:09:56 INFO:   cpu speed      :3799.791MHz
> >08:09:56 INFO:   user           :0.06%
> >08:09:56 INFO:   system         :1.81%
> >08:09:56 INFO:   idle           :96.18%
> >08:09:56 INFO:   iowait         :0.00%
> >08:09:56 INFO:   softirq        :1.95%
> >08:09:56 INFO:   cycles/byte    :2.25
> >08:09:56 INFO: cpu busy (all)   :569.22%
> >
> >[1]
> >https://lore.kernel/
> >.org%2Fall%2F20231211063726.GA4977%40linuxonhyperv3.guj3yctzbm1etfxqx2v
> >ob5hsef.xx.internal.cloudapp.net%2F&data=05%7C02%7Cschakrabarti%40micros
> >oft.com%7Ca385a5a5d661458219c208dbff47a7ab%7C72f988bf86f141af91ab2d7
> >cd011db47%7C1%7C0%7C638384455520036393%7CUnknown%7CTWFpbGZsb3d
> >8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%
> >7C3000%7C%7C%7C&sdata=kzoalzSu6frB0GIaUM5VWsz04%2FsB%2FBdXwXKb26
> >IhqkE%3D&reserved=0
> >
> >Signed-off-by: Yury Norov <yury.norov@gmail.com>
> >Co-developed-by: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
> >---
> > .../net/ethernet/microsoft/mana/gdma_main.c   | 28 +++++++++++++++++++
> > 1 file changed, 28 insertions(+)
> >
> >diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> >b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> >index 6367de0c2c2e..11e64e42e3b2 100644
> >--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> >+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> >@@ -1243,6 +1243,34 @@ void mana_gd_free_res_map(struct gdma_resource
> >*r)
> >        r->size = 0;
> > }
> >
> >+static __maybe_unused int irq_setup(unsigned int *irqs, unsigned int
> >+len, int node) {
> >+       const struct cpumask *next, *prev = cpu_none_mask;
> >+       cpumask_var_t cpus __free(free_cpumask_var);
> >+       int cpu, weight;
> >+
> >+       if (!alloc_cpumask_var(&cpus, GFP_KERNEL))
> >+               return -ENOMEM;
> >+
> >+       rcu_read_lock();
> >+       for_each_numa_hop_mask(next, node) {
> >+               weight = cpumask_weight_andnot(next, prev);
> >+               while (weight-- > 0) {
> Make it while (weight > 0) {
> >+                       cpumask_andnot(cpus, next, prev);
> >+                       for_each_cpu(cpu, cpus) {
> >+                               if (len-- == 0)
> >+                                       goto done;
> >+                               irq_set_affinity_and_hint(*irqs++,
> >topology_sibling_cpumask(cpu));
> >+                               cpumask_andnot(cpus, cpus, topology_sibling_cpumask(cpu));
> Here do --weight, else this code will traverse the same node N^2 times, where each
> node has N cpus .

Sure.

When building your series on top of this, can you please fix it
inplace?

Thanks,
Yury

> >+                       }
> >+               }
> >+               prev = next;
> >+       }
> >+done:
> >+       rcu_read_unlock();
> >+       return 0;
> >+}
> >+
> > static int mana_gd_setup_irqs(struct pci_dev *pdev)  {
> >        unsigned int max_queues_per_port = num_online_cpus();
> >--
> >2.40.1