linux-kernel - Re: [PATCH V2 net 13/20] net/ena: change driver's default timeouts

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Date:   Mon, 5 Dec 2016 20:28:17 +0200
From:   Netanel Belgazal <netanel@...apurnalabs.com>
To:     Matt Wilson <msw@...n.com>
Cc:     linux-kernel@...r.kernel.org, davem@...emloft.net,
        netdev@...r.kernel.org, dwmw@...zon.com, zorik@...apurnalabs.com,
        alex@...apurnalabs.com, saeed@...apurnalabs.com, msw@...zon.com,
        aliguori@...zon.com, nafea@...apurnalabs.com
Subject: Re: [PATCH V2 net 13/20] net/ena: change driver's default timeouts

On 12/05/2016 06:35 AM, Matt Wilson wrote:
> On Sun, Dec 04, 2016 at 03:19:31PM +0200, Netanel Belgazal wrote:
>
> ... because? (they turned out to be too aggressive, I believe.)

Yes, The timeout were too aggressive on some specific machines.

>> Signed-off-by: Netanel Belgazal <netanel@...apurnalabs.com>
>> ---
>>   drivers/net/ethernet/amazon/ena/ena_com.c    | 4 ++--
>>   drivers/net/ethernet/amazon/ena/ena_netdev.h | 7 ++++---
>>   2 files changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c b/drivers/net/ethernet/amazon/ena/ena_com.c
>> index 4147d6e..a550c8a 100644
>> --- a/drivers/net/ethernet/amazon/ena/ena_com.c
>> +++ b/drivers/net/ethernet/amazon/ena/ena_com.c
>> @@ -36,9 +36,9 @@
>>   /*****************************************************************************/
>>   
>>   /* Timeout in micro-sec */
>> -#define ADMIN_CMD_TIMEOUT_US (1000000)
>> +#define ADMIN_CMD_TIMEOUT_US (3000000)
>>   
>> -#define ENA_ASYNC_QUEUE_DEPTH 4
>> +#define ENA_ASYNC_QUEUE_DEPTH 16
> Why is this changed at the same time?

It related to the too aggressive thresholds.
On some heavy loaded system we reached to a state where the AENQ
was full so the driver missed some events.


>
>>   #define ENA_ADMIN_QUEUE_DEPTH 32
>>   
>>   #define MIN_ENA_VER (((ENA_COMMON_SPEC_VERSION_MAJOR) << \
>> diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.h b/drivers/net/ethernet/amazon/ena/ena_netdev.h
>> index c081fd3..ed42e07 100644
>> --- a/drivers/net/ethernet/amazon/ena/ena_netdev.h
>> +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.h
>> @@ -39,6 +39,7 @@
>>   #include <linux/interrupt.h>
>>   #include <linux/netdevice.h>
>>   #include <linux/skbuff.h>
>> +#include <linux/u64_stats_sync.h>
> This change seems unrelated.

Removed to a different patch (will be submitted in a new patchset)
>
>>   #include "ena_com.h"
>>   #include "ena_eth_com.h"
>> @@ -100,7 +101,7 @@
>>   /* Number of queues to check for missing queues per timer service */
>>   #define ENA_MONITORED_TX_QUEUES	4
>>   /* Max timeout packets before device reset */
>> -#define MAX_NUM_OF_TIMEOUTED_PACKETS 32
>> +#define MAX_NUM_OF_TIMEOUTED_PACKETS 128
>>   
>>   #define ENA_TX_RING_IDX_NEXT(idx, ring_size) (((idx) + 1) & ((ring_size) - 1))
>>   
>> @@ -116,9 +117,9 @@
>>   #define ENA_IO_IRQ_IDX(q)		(ENA_IO_IRQ_FIRST_IDX + (q))
>>   
>>   /* ENA device should send keep alive msg every 1 sec.
>> - * We wait for 3 sec just to be on the safe side.
>> + * We wait for 6 sec just to be on the safe side.
>>    */
>> -#define ENA_DEVICE_KALIVE_TIMEOUT	(3 * HZ)
>> +#define ENA_DEVICE_KALIVE_TIMEOUT	(6 * HZ)
>>   
>>   #define ENA_MMIO_DISABLE_REG_READ	BIT(0)
>>