Re: [dpdk-dev] [PATCH] net/iavf: fix small probabilistic probe failure

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Qiming Chen
> Sent: Saturday, September 11, 2021 4:05 PM
> To: dev@dpdk.org
> Cc: Xing, Beilei <beilei.xing@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>;
> Qiming Chen <chenqiming_huawei@163.com>; stable@dpdk.org
> Subject: [dpdk-dev] [PATCH] net/iavf: fix small probabilistic probe failure
> 
> In the embedded RTOS environment, the x722 controller Ethernet card of the
> d2146nt chip, the vfio user mode driver takes over 8 vf ports in turn, but
> iavf_check_vf_reset_done will probably fail.
> 
> This issue has been discussed with intel&dpdk experts for 3 rounds before, and
> the version matching is no problem, and there is no substantial progress.
> 1) Learning from the implementation of the i40evf kernel driver locally, after
> modifying the polling time from 1 second to 5s,

Increase timeout from 1s to 5s may give bad user experience in the case when a vf is not expected to be init successfully due to some wrong ops.
Maybe its better to introduce a compile option or devargs for this?
 

> 2) In the same way, by checking and checking, it is found that the probability
> of vf sending a command to the interrupt thread receiving the message will
> occur for more than 12s, and there is no failure, so the time is adjusted to 15s.
> 
> the repeated restart process took over the start port test, and it was found that
> this probability was reduced to an order of magnitude acceptable to the user.
> 
> The patch cannot fundamentally solve the failure problem, but it greatly slows
> down the probability of the problem. The modification is based on the i40evf
> kernel driver.
> 
> Fixes: 22b123a36d07 ("net/avf: initialize PMD")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Qiming Chen <chenqiming_huawei@163.com>
> ---
>  drivers/net/iavf/iavf.h       | 2 +-
>  drivers/net/iavf/iavf_vchnl.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/iavf/iavf.h b/drivers/net/iavf/iavf.h index
> b3bd078111..b3732d1185 100644
> --- a/drivers/net/iavf/iavf.h
> +++ b/drivers/net/iavf/iavf.h
> @@ -16,7 +16,7 @@
> 
>  #define IAVF_AQ_LEN               32
>  #define IAVF_AQ_BUF_SZ            4096
> -#define IAVF_RESET_WAIT_CNT       50
> +#define IAVF_RESET_WAIT_CNT       250
>  #define IAVF_BUF_SIZE_MIN         1024
>  #define IAVF_FRAME_SIZE_MAX       9728
>  #define IAVF_QUEUE_BASE_ADDR_UNIT 128
> diff --git a/drivers/net/iavf/iavf_vchnl.c b/drivers/net/iavf/iavf_vchnl.c index
> 2f39c2077c..25066419b0 100644
> --- a/drivers/net/iavf/iavf_vchnl.c
> +++ b/drivers/net/iavf/iavf_vchnl.c
> @@ -23,7 +23,7 @@
>  #include "iavf.h"
>  #include "iavf_rxtx.h"
> 
> -#define MAX_TRY_TIMES 200
> +#define MAX_TRY_TIMES 1500
>  #define ASQ_DELAY_MS  10
> 
>  static uint32_t
> --
> 2.30.1.windows.1