[dpdk-dev] [PATCH V3 4/4] app/testpmd: show example to handle hot unplug

[Guo, Jia]

matan


On 6/27/2018 2:05 PM, Matan Azrad wrote:
> Hi Guo
>
> From: Guo, Jia
>> Sent: Wednesday, June 27, 2018 6:56 AM
>> To: Matan Azrad <matan at mellanox.com>; stephen at networkplumber.org;
>> bruce.richardson at intel.com; ferruh.yigit at intel.com;
>> konstantin.ananyev at intel.com; gaetan.rivet at 6wind.com;
>> jingjing.wu at intel.com; Thomas Monjalon <thomas at monjalon.net>;
>> Mordechay Haimovsky <motih at mellanox.com>; harry.van.haaren at intel.com;
>> qi.z.zhang at intel.com; shaopeng.he at intel.com; bernard.iremonger at intel.com
>> Cc: jblunck at infradead.org; shreyansh.jain at nxp.com; dev at dpdk.org;
>> helin.zhang at intel.com
>> Subject: Re: [PATCH V3 4/4] app/testpmd: show example to handle hot unplug
>>
>> hi, mantan
>>
>>
>> On 6/27/2018 1:07 AM, Matan Azrad wrote:
>>> Hi Jeff
>>>
>>> Continue session from last version + more comments\question.
>>>
>>> From: Jeff Guo
>>>> Sent: Tuesday, June 26, 2018 6:36 PM
>>>> To: stephen at networkplumber.org; bruce.richardson at intel.com;
>>>> ferruh.yigit at intel.com; konstantin.ananyev at intel.com;
>>>> gaetan.rivet at 6wind.com; jingjing.wu at intel.com; Thomas Monjalon
>>>> <thomas at monjalon.net>; Mordechay Haimovsky <motih at mellanox.com>;
>>>> Matan Azrad <matan at mellanox.com>; harry.van.haaren at intel.com;
>>>> qi.z.zhang at intel.com; shaopeng.he at intel.com;
>>>> bernard.iremonger at intel.com
>>>> Cc: jblunck at infradead.org; shreyansh.jain at nxp.com; dev at dpdk.org;
>>>> jia.guo at intel.com; helin.zhang at intel.com
>>>> Subject: [PATCH V3 4/4] app/testpmd: show example to handle hot
>>>> unplug
>>>>
>>>> Use testpmd for example, to show how an application smoothly handle
>>>> failure when device being hot unplug. If app have enabled the device
>>>> event monitor and register the hot plug event’s callback before
>>>> running, once app detect the removal event, the callback would be
>>>> called. It will first stop the packet forwarding, then stop the port,
>>>> close the port, and finally detach the port to remove the device out from the
>> device lists.
>>>> Signed-off-by: Jeff Guo <jia.guo at intel.com>
>>>> ---
>>>> v3->v2:
>>>> delete some unused check
>>>> ---
>>>>    app/test-pmd/testpmd.c | 22 +++++++++++++++++-----
>>>>    1 file changed, 17 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c index
>>>> 24c1998..2ee5621 100644
>>>> --- a/app/test-pmd/testpmd.c
>>>> +++ b/app/test-pmd/testpmd.c
>>>> @@ -1951,9 +1951,10 @@ eth_dev_event_callback_unregister(void)
>>>>    void
>>>>    attach_port(char *identifier)
>>>>    {
>>>> -	portid_t pi = 0;
>>>>    	unsigned int socket_id;
>>>>
>>>> +	portid_t pi = rte_eth_dev_count_avail();
>>>> +
>>> I don't understand this change... can you explain?
>> think about if there are 2 or more device have been attached? The new device
>> should not always add into port 0, right?
> I think you miss here something, you are getting the port id from ethdev, you are just passing a pointer to get it.
> I think you should remove this change too.

ok, seems i am missing something, let me check.

>>>>    	printf("Attaching a new port...\n");
>>>>
>>>>    	if (identifier == NULL) {
>>>> @@ -2125,16 +2126,22 @@ check_all_ports_link_status(uint32_t
>>>> port_mask) static void  rmv_event_callback(void *arg)  {
>>>> +	struct rte_eth_dev *dev;
>>>> +
>>>>    	int need_to_start = 0;
>>>>    	int org_no_link_check = no_link_check;
>>>>    	portid_t port_id = (intptr_t)arg;
>>>>
>>>>    	RTE_ETH_VALID_PORTID_OR_RET(port_id);
>>>> +	dev = &rte_eth_devices[port_id];
>>>> +
>>>> +	printf("removing device %s\n", dev->device->name);
>>>>
>>>>    	if (!test_done && port_is_forwarding(port_id)) {
>>>>    		need_to_start = 1;
>>>>    		stop_packet_forwarding();
>>>>    	}
>>>> +
>>> I don't think you need to change anything in this function.
>>> You can add the print in the caller code.
>> ok, i am fine for your point.
>>
>>>>    	no_link_check = 1;
>>>>    	stop_port(port_id);
>>>>    	no_link_check = org_no_link_check;
>>> Suggestion for synchronization:
>>> Don't register to ethdev RMV event if EAL hotplug is enabled.
>> i think that what you propose might be a chose right now, and might need we
>> think more about the better for all, but do you agree it is better split it in
>> another fix patch, to let it patch focus on the feature propose and implement?
> So, Are you suggesting to insert a bug and then to fix it ?:)
>
> My suggestion:
> Add a prior patch to depend the ethdev RMV event by a user parameter (can be your hotplug parameter and should be true by default).
> In this patch add one more mode to the parameter to enable hotplug by the EAL.
>
> So finally the options of hotplug parameter can be:
> 0 - for no hotplug handle.
> 1 - ethdev hotplug (should be the default)
> 2 - EAL hotplug
>
> What do you think?

sure, i think you absolutely know i don't want to add any bug here :) 
just want to make it more focus and clear.
your propose looks fine by me. good idea, thanks.
please check my v4 patch set.

>>>> @@ -2196,6 +2203,9 @@ static void
>>>>    eth_dev_event_callback(char *device_name, enum rte_dev_event_type
>> type,
>>>>    			     __rte_unused void *arg)
>>>>    {
>>>> +	uint16_t port_id;
>>>> +	int ret;
>>>> +
>>>>    	if (type >= RTE_DEV_EVENT_MAX) {
>>>>    		fprintf(stderr, "%s called upon invalid event %d\n",
>>>>    			__func__, type);
>>>> @@ -2206,9 +2216,12 @@ eth_dev_event_callback(char *device_name,
>> enum
>>>> rte_dev_event_type type,
>>>>    	case RTE_DEV_EVENT_REMOVE:
>>>>    		RTE_LOG(ERR, EAL, "The device: %s has been removed!\n",
>>>>    			device_name);
>>>> -		/* TODO: After finish failure handle, begin to stop
>>>> -		 * packet forward, stop port, close port, detach port.
>>>> -		 */
>>>> +		ret = rte_eth_dev_get_port_by_name(device_name, &port_id);
>>>> +		if (ret) {
>>>> +			printf("can not get port by device %s!\n",
>>>> device_name);
>>>> +			return;
>>>> +		}
>>>> +		rmv_event_callback((void *)(intptr_t)port_id);
>>>>    		break;
>>>>    	case RTE_DEV_EVENT_ADD:
>>>>    		RTE_LOG(ERR, EAL, "The device: %s has been added!\n", @@ -
>>>> 2736,7 +2749,6 @@ main(int argc, char** argv)
>>>>    			return -1;
>>>>    		}
>>>>    		eth_dev_event_callback_register();
>>>> -
>>>>    	}
>>>>
>>>>    	if (start_port(RTE_PORT_ALL) != 0)
>>>> --
>>>> 2.7.4