On 12/1/2017 6:22 PM, Vlad Zolotarov wrote:
>
>
> On 12/01/2017 06:51 PM, Ferruh Yigit wrote:
>> On 12/1/2017 2:17 PM, Vlad Zolotarov wrote:
>>>
>>> On 11/30/2017 09:29 PM, Ferruh Yigit wrote:
>>>> remove RTE_ETHDEV_HAS_LRO_SUPPORT flag from header.
>>>>
>>>> Flag seems added with the patch that adds LRO support, and intention
>>>> looks like giving a pointer to application that library supports LRO.
>>> Exactly. Removing this flag may make the existing application "think" that
>>> LRO
>>> is not supported.
>>> Why do you want to remove it to begin with?
>> I agree that this is a little controversial, and I don't have a strong
>> opinion
>> about it, I thought twice before sending or not sending the patch :)
>>
>> This flag can be useful for the applications that use different versions of
>> the
>> DPDK library (with the ones does and doesn't support LRO), so that
>> application
>> can be more portable.
>> I would understand a dynamic approach, which would be useful for distributed
>> applications that you don't know and can't control what version of the DPDK
>> library used.
>> But here to benefit from this flag you need to compile your application
>> against
>> DPDK library, and if you are compiling it you already know if your DPDK
>> supports
>> LRO or not. And this is not something keeps changing platform to platform
>> etc,
>> after a specific release LRO is always supported.
>
> True but DPDK is usually not a part of your source tree - it (should) come as
> a
> library and currently there isn't any proper way to query feature set.
> This flag was also added after a lot of consideration as a rather ugly
> compromise since there wasn't (and there isn't) a proper way to do that at
> that
> (this) time. See more on that below.
>
>>
>> And this is the only capability support flag in the ethdev, there are many
>> new
>> features introduced in each release but they are not advertised by a
>> capability
>> flag. Only having LRO flag can be confusing.
>>
>> _Perhaps_ DPDK should have a way to expose the supported features, and a
>> dynamic
>> runtime way can be better option than compile time macros, but it should be
>> generic nothing specific to LRO support.
>
> IMO it's not "perhaps" it's a "must" _however_
This is even wider than ethdev, more like in DPDK scope, we need someone to
attack this issue.
> you can't remove this flag without giving some other tool to do the same.
Fair enough, I will drop the patch.
> Querying a DPDK version would be a wrong direction because some Linux
> distributions (yes, I'm talking about you, Ubuntu) tend to have it's own trees
> with their own backports and these trees may be light years ahead in their
> patch
> level compared to vanilla trees with the same version.
+1 to have better way than version check.
>
>>
>>>> Fixes: 8eecb3295aed ("ixgbe: add LRO support")
>>>> Cc: vl...@cloudius-systems.com
>>>>
>>>> Signed-off-by: Ferruh Yigit <ferruh.yi...@intel.com>
>>>> ---
>>>> lib/librte_ether/rte_ethdev.h | 3 ---
>>>> 1 file changed, 3 deletions(-)
>>>>
>>>> diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
>>>> index 341c2d624..e620c3706 100644
>>>> --- a/lib/librte_ether/rte_ethdev.h
>>>> +++ b/lib/librte_ether/rte_ethdev.h
>>>> @@ -172,9 +172,6 @@ extern "C" {
>>>>
>>>> #include <stdint.h>
>>>>
>>>> -/* Use this macro to check if LRO API is supported */
>>>> -#define RTE_ETHDEV_HAS_LRO_SUPPORT
>>>> -
>>>> #include <rte_log.h>
>>>> #include <rte_interrupts.h>
>>>> #include <rte_dev.h>
>
