2012-11-02 16:01:45

by Shan Wei

Subject: [PATCH 4/9] net: openvswitch: use this_cpu_ptr per-cpu helper

From: Shan Wei <[email protected]>

no change vs v1.

Lots of drivers use this kind to read/write per-cpu variable.
stats = this_cpu_ptr(dp->stats_percpu);
u64_stats_update_begin(&stats->sync);
stats->tx_packets++;
u64_stats_update_begin(&stats->sync);


Signed-off-by: Shan Wei <[email protected]>
---
net/openvswitch/datapath.c | 4 ++--
net/openvswitch/vport.c | 5 ++---
2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 4c4b62c..77d16a5 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -208,7 +208,7 @@ void ovs_dp_process_received_packet(struct vport *p, struct sk_buff *skb)
int error;
int key_len;

- stats = per_cpu_ptr(dp->stats_percpu, smp_processor_id());
+ stats = this_cpu_ptr(dp->stats_percpu);

/* Extract flow from 'skb' into 'key'. */
error = ovs_flow_extract(skb, p->port_no, &key, &key_len);
@@ -282,7 +282,7 @@ int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb,
return 0;

err:
- stats = per_cpu_ptr(dp->stats_percpu, smp_processor_id());
+ stats = this_cpu_ptr(dp->stats_percpu);

u64_stats_update_begin(&stats->sync);
stats->n_lost++;
diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
index 03779e8..70af0be 100644
--- a/net/openvswitch/vport.c
+++ b/net/openvswitch/vport.c
@@ -333,8 +333,7 @@ void ovs_vport_receive(struct vport *vport, struct sk_buff *skb)
{
struct vport_percpu_stats *stats;

- stats = per_cpu_ptr(vport->percpu_stats, smp_processor_id());
-
+ stats = this_cpu_ptr(vport->percpu_stats);
u64_stats_update_begin(&stats->sync);
stats->rx_packets++;
stats->rx_bytes += skb->len;
@@ -359,7 +358,7 @@ int ovs_vport_send(struct vport *vport, struct sk_buff *skb)
if (likely(sent)) {
struct vport_percpu_stats *stats;

- stats = per_cpu_ptr(vport->percpu_stats, smp_processor_id());
+ stats = this_cpu_ptr(vport->percpu_stats);

u64_stats_update_begin(&stats->sync);
stats->tx_packets++;
--
1.7.1

2012-11-02 17:46:50

by Christoph Lameter (Ampere)

Subject: Re: [PATCH 4/9] net: openvswitch: use this_cpu_ptr per-cpu helper

On Sat, 3 Nov 2012, Shan Wei wrote:

> +++ b/net/openvswitch/datapath.c
> @@ -208,7 +208,7 @@ void ovs_dp_process_received_packet(struct vport *p, struct sk_buff *skb)
> int error;
> int key_len;
>
> - stats = per_cpu_ptr(dp->stats_percpu, smp_processor_id());
> + stats = this_cpu_ptr(dp->stats_percpu);
>
> /* Extract flow from 'skb' into 'key'. */
> error = ovs_flow_extract(skb, p->port_no, &key, &key_len);
> @@ -282,7 +282,7 @@ int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb,
> return 0;
>
> err:
> - stats = per_cpu_ptr(dp->stats_percpu, smp_processor_id());
> + stats = this_cpu_ptr(dp->stats_percpu);
>
> u64_stats_update_begin(&stats->sync);
> stats->n_lost++;
> diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
> index 03779e8..70af0be 100644
> --- a/net/openvswitch/vport.c
> +++ b/net/openvswitch/vport.c
> @@ -333,8 +333,7 @@ void ovs_vport_receive(struct vport *vport, struct sk_buff *skb)
> {
> struct vport_percpu_stats *stats;
>
> - stats = per_cpu_ptr(vport->percpu_stats, smp_processor_id());
> -
> + stats = this_cpu_ptr(vport->percpu_stats);
> u64_stats_update_begin(&stats->sync);
> stats->rx_packets++;
> stats->rx_bytes += skb->len;
> @@ -359,7 +358,7 @@ int ovs_vport_send(struct vport *vport, struct sk_buff *skb)
> if (likely(sent)) {
> struct vport_percpu_stats *stats;
>
> - stats = per_cpu_ptr(vport->percpu_stats, smp_processor_id());
> + stats = this_cpu_ptr(vport->percpu_stats);
>
> u64_stats_update_begin(&stats->sync);
> stats->tx_packets++;

Use this_cpu_inc(vport->percpu_stats->packets) here?

2012-11-08 14:22:50

by Shan Wei

Subject: Re: [PATCH 4/9] net: openvswitch: use this_cpu_ptr per-cpu helper

Christoph Lameter said, at 2012/11/3 1:46:
>> u64_stats_update_begin(&stats->sync);
>> stats->tx_packets++;
>
> Use this_cpu_inc(vport->percpu_stats->packets) here?

Lots of network drivers use u64_stats_sync infrastructure for statistics
on 32bit or 64bit hosts no matter how many members in per-cpu variable.

keep them be consistent, so no plan to change them.

Thanks

2012-11-08 17:19:00

by Christoph Lameter (Ampere)

Subject: Re: [PATCH 4/9] net: openvswitch: use this_cpu_ptr per-cpu helper

On Thu, 8 Nov 2012, Shan Wei wrote:

> Christoph Lameter said, at 2012/11/3 1:46:
> >> u64_stats_update_begin(&stats->sync);
> >> stats->tx_packets++;
> >
> > Use this_cpu_inc(vport->percpu_stats->packets) here?
>
> Lots of network drivers use u64_stats_sync infrastructure for statistics

So they would all have an advantage from the patch.

2012-11-09 01:40:06

by Shan Wei

Subject: Re: [PATCH 4/9] net: openvswitch: use this_cpu_ptr per-cpu helper

Christoph Lameter said, at 2012/11/9 1:18:
> On Thu, 8 Nov 2012, Shan Wei wrote:
>
>> Christoph Lameter said, at 2012/11/3 1:46:
>>>> u64_stats_update_begin(&stats->sync);
>>>> stats->tx_packets++;
>>>
>>> Use this_cpu_inc(vport->percpu_stats->packets) here?
>>
>> Lots of network drivers use u64_stats_sync infrastructure for statistics
>
> So they would all have an advantage from the patch.

I will try to do the optimizing next time in another patchset which not included
in this series patchset.

I will submit v3 version of this series after testing today.

Thanks