Re: [dpdk-dev] [dpdk-stable] [PATCH] net/i40e: extend the polling times of vf reset

[David Marchand <david.marchand@redhat.com>]

On Mon, Sep 6, 2021 at 9:08 AM Qiming Chen <chenqiming_huawei@163.com> wrote:
>
> 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 i40evf_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. The official website contacted external experts,
> but there was no response afterwards. Learning from the implementation
> of the i40evf kernel driver locally, after modifying the polling time
> from 1 second to 5s, 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: 5c9222058df7 ("i40e: move to drivers/net/")

This Fixes: is not the right one as this commit only moved code around.


> Cc: stable@dpdk.org
>
> Signed-off-by: Qiming Chen <chenqiming_huawei@163.com>
> ---
>  drivers/net/i40e/i40e_ethdev_vf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/i40e/i40e_ethdev_vf.c b/drivers/net/i40e/i40e_ethdev_vf.c
> index f64db72e9a..924da8dfb4 100644
> --- a/drivers/net/i40e/i40e_ethdev_vf.c
> +++ b/drivers/net/i40e/i40e_ethdev_vf.c
> @@ -42,7 +42,7 @@
>  /* busy wait delay in msec */
>  #define I40EVF_BUSY_WAIT_DELAY 10
>  #define I40EVF_BUSY_WAIT_COUNT 50
> -#define MAX_RESET_WAIT_CNT     20
> +#define MAX_RESET_WAIT_CNT     100

Copying more Intel maintainers.

This mechanism is common to various Intel hw/drivers.
Does this issue only affect i40e hw or should we also consider the
issue with other hw/drivers?

drivers/net/i40e/i40e_ethdev_vf.c:#define MAX_RESET_WAIT_CNT     20
drivers/net/i40e/i40e_ethdev_vf.c:      for (i = 0; i <
MAX_RESET_WAIT_CNT; i++) {
drivers/net/i40e/i40e_ethdev_vf.c:      if (i >= MAX_RESET_WAIT_CNT)
drivers/net/iavf/iavf.h:#define IAVF_RESET_WAIT_CNT       50
drivers/net/iavf/iavf_ethdev.c: for (i = 0; i < IAVF_RESET_WAIT_CNT; i++) {
drivers/net/iavf/iavf_ethdev.c: if (i >= IAVF_RESET_WAIT_CNT)
drivers/net/ice/ice_dcf.c:#define ICE_DCF_RESET_WAIT_CNT       50
drivers/net/ice/ice_dcf.c:      for (i = 0; i < ICE_DCF_RESET_WAIT_CNT; i++) {
drivers/net/ice/ice_dcf.c:      if (i >= ICE_DCF_RESET_WAIT_CNT)



-- 
David Marchand