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From: Nageswara Rao <nagpen75@gmail.com>
To: stephen@networkplumber.org, kparameshwar@vmware.com
Cc: dev@dpdk.org, ASHIQUE CK <ckashiquekvk@gmail.com>
Subject: Re: DPDK22 issue: Unable to set more than 4 queues in Azure
Date: Mon, 26 Jun 2023 21:59:36 +0530	[thread overview]
Message-ID: <CA+RWRMFOQBpT2RYxU3EEydyr4qJKadHaJz6N=eBm8_2WV2mjWA@mail.gmail.com> (raw)
In-Reply-To: <CA+RWRMEps0Kv6RV9rZnd5CDwtQS3DCMbYrxi+0XXKLfFvkPaYQ@mail.gmail.com>

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Issue is because of tap_mp_req_on_rxtx() sending msg.num_fds more
than RTE_MP_MAX_FD_NUM fds for queues > 4.
Looks like these tap driver changes are added as part of the below patch
http://patches.dpdk.org/project/dpdk/patch/20220121042944.23929-1-kumaraparamesh92@gmail.com/


On Mon, Jun 26, 2023 at 3:53 PM Nageswara Rao <nagpen75@gmail.com> wrote:

> Yes, we are using vdev_netvsc. Native netvsc PMD we are observing issues
> in enabling multiple queues.
> Though we have 6 DPDK cores, unable to configure more than 4 queues.
>
> On Mon, Jun 26, 2023 at 12:18 AM Stephen Hemminger <
> stephen@networkplumber.org> wrote:
>
>> On Thu, 22 Jun 2023 22:06:10 +0530
>> Nageswara Rao <nagpen75@gmail.com> wrote:
>>
>> > Hi All,
>> >
>> > We are observing the following issue with DPDK22.11. We didn’t find any
>> > upstream patches for this issue on the DPDK github. Is there any known
>> > issue, please let us know.
>> >
>> >
>> >
>> > *Issue:*
>> >
>> > On Azure platform, we are unable to configure more than 4 queues. When
>> we
>> > try to configure more than 4 queues its failing with “EAL: Cannot send
>> more
>> > than 8 FDs” error.
>> >
>> > Here I am pasting the working and failing testpmd logs.
>> >
>> > Please note that this issue is not observed in DPDK 21.11.
>> >
>>
>> You should be using the native netvsc PMD, not the
>> vdev_netvsc,failsafe,tap kludge.
>>
>> I don't work on Azure any more but I suspect the issue is that the default
>> in the kernel for TAP is for the number of queues == number of cores.
>>
>> You aren't going to see any real benefit from having more queues than
>> the number of DPDK cores.
>>
>>

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      parent reply	other threads:[~2023-06-26 16:29 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-22 16:36 Nageswara Rao
2023-06-25 18:48 ` Stephen Hemminger
2023-06-26 10:23   ` Nageswara Rao
2023-06-26 16:25     ` Stephen Hemminger
2023-06-26 16:29     ` Nageswara Rao [this message]

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