On 28/10/15 15:59, Eric Dumazet wrote:
> On Wed, 2015-10-28 at 15:01 +0000, Shradha Shah wrote:
>> From: Daniel Pieczko <dpiec...@solarflare.com>
>>
>> When the interrupt servicing a channel is on a NUMA node that is
>> not local to the device, performance is improved by allocating
>> rx pages on the node local to the interrupt (remote to the device)
>>
>> The performance-optimal case, where interrupts and applications
>> are pinned to CPUs on the same node as the device, is not altered
>> by this change.
>>
>> This change gave a 1% improvement in transaction rate using Nginx
>> with all interrupts and Nginx threads on the node remote to the
>> device. It also gave a small reduction in round-trip latency,
>> again with the interrupt and application on a different node to
>> the device.
>>
>> Allocating rx pages based on the channel->irq_node value is only
>> valid for the initial driver-load interrupt affinities; if an
>> interrupt is moved later, the wrong node may be used for the
>> allocation.
>>
>> Signed-off-by: Shradha Shah <ss...@solarflare.com>
>> ---
>> drivers/net/ethernet/sfc/efx.c | 1 +
>> drivers/net/ethernet/sfc/net_driver.h | 3 +++
>> drivers/net/ethernet/sfc/rx.c | 14 +++++++++-----
>> 3 files changed, 13 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
>> index 974637d..89fbd03 100644
>> --- a/drivers/net/ethernet/sfc/efx.c
>> +++ b/drivers/net/ethernet/sfc/efx.c
>> @@ -445,6 +445,7 @@ efx_alloc_channel(struct efx_nic *efx, int i, struct
>> efx_channel *old_channel)
>> channel->efx = efx;
>> channel->channel = i;
>> channel->type = &efx_default_channel_type;
>> + channel->irq_node = NUMA_NO_NODE;
>>
>> for (j = 0; j < EFX_TXQ_TYPES; j++) {
>> tx_queue = &channel->tx_queue[j];
>> diff --git a/drivers/net/ethernet/sfc/net_driver.h
>> b/drivers/net/ethernet/sfc/net_driver.h
>> index ad56231..0ab9080a 100644
>> --- a/drivers/net/ethernet/sfc/net_driver.h
>> +++ b/drivers/net/ethernet/sfc/net_driver.h
>> @@ -419,6 +419,7 @@ enum efx_sync_events_state {
>> * @sync_events_state: Current state of sync events on this channel
>> * @sync_timestamp_major: Major part of the last ptp sync event
>> * @sync_timestamp_minor: Minor part of the last ptp sync event
>> + * @irq_node: NUMA node of interrupt
>> */
>> struct efx_channel {
>> struct efx_nic *efx;
>> @@ -477,6 +478,8 @@ struct efx_channel {
>> enum efx_sync_events_state sync_events_state;
>> u32 sync_timestamp_major;
>> u32 sync_timestamp_minor;
>> +
>> + int irq_node;
>> };
>>
>> #ifdef CONFIG_NET_RX_BUSY_POLL
>> diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
>> index 3f0e129..c5ef1e8 100644
>> --- a/drivers/net/ethernet/sfc/rx.c
>> +++ b/drivers/net/ethernet/sfc/rx.c
>> @@ -168,11 +168,15 @@ static int efx_init_rx_buffers(struct efx_rx_queue
>> *rx_queue, bool atomic)
>> * context in such a case. So, use __GFP_NO_WARN
>> * in case of atomic.
>> */
>> - page = alloc_pages(__GFP_COLD | __GFP_COMP |
>> - (atomic ?
>> - (GFP_ATOMIC | __GFP_NOWARN)
>> - : GFP_KERNEL),
>> - efx->rx_buffer_order);
>> + struct efx_channel *channel;
>> +
>> + channel = efx_rx_queue_channel(rx_queue);
>> + page = alloc_pages_node(channel->irq_node, __GFP_COMP |
>> + (atomic ?
>> + (GFP_ATOMIC | __GFP_NOWARN)
>> + : GFP_KERNEL),
>> + efx->rx_buffer_order);
>> +
>> if (unlikely(page == NULL))
>> return -ENOMEM;
>> dma_addr =
>>
>
> Sorry, I do not understand this patch, and why the following one is not
> squashed on this one.
>
> irq_node is always NUMA_NO_NODE (in this patch)
>
> So you claim a 1% improvement, switching from alloc_pages(...) to
> alloc_pages_node(NUMA_NO_NODE, ...) ???
>
You're correct that this doesn't make sense as it is. There is something
missing in this patch (channel->irq_node should be set) and also changing the
order of some patches could make this clearer. The series will need to be
resent.
Daniel
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