[dpdk-stable] [PATCH v3] examples/vhost: change the default value of NIC's max queues

[dpdk-stable] [PATCH v3] examples/vhost: change the default value of NIC's max queues

[Wenwu Ma]

vswitch can't launch with a 40G i40e port due to device start fails
if NIC’s max queues > the default number of 128, so, we changed
the default value from 128 to 512.

Fixes: 4796ad63ba1f ("examples/vhost: import userspace vhost application")
Cc: stable@dpdk.org

Signed-off-by: Wenwu Ma <wenwux.ma@intel.com>
---
 examples/vhost/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index bc3d71c898..36969a4de5 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -29,7 +29,7 @@
 #include "main.h"
 
 #ifndef MAX_QUEUES
-#define MAX_QUEUES 128
+#define MAX_QUEUES 512
 #endif
 
 /* the maximum number of external ports supported */
-- 
2.25.1

Re: [dpdk-stable] [PATCH v3] examples/vhost: change the default value of NIC's max queues

[Maxime Coquelin]

On 10/15/21 18:48, Wenwu Ma wrote:
> vswitch can't launch with a 40G i40e port due to device start fails
> if NIC’s max queues > the default number of 128, so, we changed
> the default value from 128 to 512.
> 
> Fixes: 4796ad63ba1f ("examples/vhost: import userspace vhost application")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Wenwu Ma <wenwux.ma@intel.com>
> ---
>   examples/vhost/main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/examples/vhost/main.c b/examples/vhost/main.c
> index bc3d71c898..36969a4de5 100644
> --- a/examples/vhost/main.c
> +++ b/examples/vhost/main.c
> @@ -29,7 +29,7 @@
>   #include "main.h"
>   
>   #ifndef MAX_QUEUES
> -#define MAX_QUEUES 128
> +#define MAX_QUEUES 512
>   #endif
>   
>   /* the maximum number of external ports supported */
> 

As discussed, this is far from ideal, but let's use our time to remove
gaps in Vhost testing with testpmd so that we can remove this example
later.

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

Re: [dpdk-stable] [PATCH v3] examples/vhost: change the default value of NIC's max queues

[Maxime Coquelin]

On 10/15/21 18:48, Wenwu Ma wrote:
> vswitch can't launch with a 40G i40e port due to device start fails
> if NIC’s max queues > the default number of 128, so, we changed
> the default value from 128 to 512.
> 
> Fixes: 4796ad63ba1f ("examples/vhost: import userspace vhost application")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Wenwu Ma <wenwux.ma@intel.com>
> ---
>   examples/vhost/main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 

Applied to dpdk-next-virtio/main.

Thanks,
Maxime

Re: [dpdk-stable] [dpdk-dev] [PATCH v3] examples/vhost: change the default value of NIC's max queues

[Ferruh Yigit]

On 10/15/2021 5:48 PM, Wenwu Ma wrote:
> vswitch can't launch with a 40G i40e port due to device start fails

what is 'vswitch' that is referred? I expect what can't launch should
be this sample app but why referring it as 'vswitch'?

Also patch title describes what is done, better to describe why it is done,
like:
examples/vhost: fix init for devices that has big max queue number

btw, why a device with big max queue number causes failure in the sample app?
Can you please provide more detail on the error? What and why fails on
device start?

> if NIC’s max queues > the default number of 128, so, we changed
> the default value from 128 to 512.
> 
> Fixes: 4796ad63ba1f ("examples/vhost: import userspace vhost application")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Wenwu Ma <wenwux.ma@intel.com>
> ---
>   examples/vhost/main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/examples/vhost/main.c b/examples/vhost/main.c
> index bc3d71c898..36969a4de5 100644
> --- a/examples/vhost/main.c
> +++ b/examples/vhost/main.c
> @@ -29,7 +29,7 @@
>   #include "main.h"
>   
>   #ifndef MAX_QUEUES
> -#define MAX_QUEUES 128
> +#define MAX_QUEUES 512
>   #endif
>   
>   /* the maximum number of external ports supported */
> 

[dpdk-stable] [PATCH v4] examples/vhost: fix failure to launch dpdk-vhost

[Wenwu Ma]

When the default max queue value of vhost is 128, dpdk-vhost will fail to
launch with a 40G i40e port due to the mbuf allocation of the port queue fails.
Therefore, we modify the default value of max queue from 128 to 512,
it will ensure that there are enough mbufs.

Fixes: 4796ad63ba1f ("examples/vhost: import userspace vhost application")
Cc: stable@dpdk.org

Signed-off-by: Wenwu Ma <wenwux.ma@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 examples/vhost/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index bc3d71c898..36969a4de5 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -29,7 +29,7 @@
 #include "main.h"
 
 #ifndef MAX_QUEUES
-#define MAX_QUEUES 128
+#define MAX_QUEUES 512
 #endif
 
 /* the maximum number of external ports supported */
-- 
2.25.1

Re: [dpdk-stable] [PATCH v4] examples/vhost: fix failure to launch dpdk-vhost

[Xia, Chenbo]

Hi,

> -----Original Message-----
> From: Ma, WenwuX <wenwux.ma@intel.com>
> Sent: Wednesday, November 3, 2021 10:17 PM
> To: dev@dpdk.org
> Cc: maxime.coquelin@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>; Yigit,
> Ferruh <ferruh.yigit@intel.com>; Jiang, Cheng1 <cheng1.jiang@intel.com>; Hu,
> Jiayu <jiayu.hu@intel.com>; Yang, YvonneX <yvonnex.yang@intel.com>; Ma, WenwuX
> <wenwux.ma@intel.com>; stable@dpdk.org
> Subject: [PATCH v4] examples/vhost: fix failure to launch dpdk-vhost
> 
> When the default max queue value of vhost is 128, dpdk-vhost will fail to
> launch with a 40G i40e port due to the mbuf allocation of the port queue fails.
> Therefore, we modify the default value of max queue from 128 to 512,
> it will ensure that there are enough mbufs.
> 
> Fixes: 4796ad63ba1f ("examples/vhost: import userspace vhost application")
> Cc: stable@dpdk.org

When I was tracking the bad commit, I notice this change is on purpose to save hugepages:

commit f17eb179046962fdc29c3609b1c9bd46bfefa4f5
Author: Bernard Iremonger <bernard.iremonger@intel.com>
Date:   Thu Dec 10 15:49:17 2015 +0000

    examples/vhost: reduce number of hugepages needed

    Add #ifndef MAX_QUEUES to change MAX_QUEUES at compile time if needed.
    Change MAX_QUEUES from 512 to 128 to reduce the number of hugepages
    required by the vhost-switch program.

    To change MAX_QUEUES add '-D MAX_QUEUES=512' to the EXTRA_CFLAGS variable,
    before building the application.

    Signed-off-by: Bernard Iremonger <bernard.iremonger@intel.com>
    Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

So as there's a way to solve the problem (although not perfect), I would suggest
using the compiler flag to do tests with the specific NIC.

If no one has objection, let's drop the patch.

Thanks,
Chenbo

> 
> Signed-off-by: Wenwu Ma <wenwux.ma@intel.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  examples/vhost/main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/examples/vhost/main.c b/examples/vhost/main.c
> index bc3d71c898..36969a4de5 100644
> --- a/examples/vhost/main.c
> +++ b/examples/vhost/main.c
> @@ -29,7 +29,7 @@
>  #include "main.h"
> 
>  #ifndef MAX_QUEUES
> -#define MAX_QUEUES 128
> +#define MAX_QUEUES 512
>  #endif
> 
>  /* the maximum number of external ports supported */
> --
> 2.25.1

Re: [dpdk-stable] [PATCH v4] examples/vhost: fix failure to launch dpdk-vhost

[Maxime Coquelin]

Hi Chenbo,

On 11/3/21 05:58, Xia, Chenbo wrote:
> Hi,
> 
>> -----Original Message-----
>> From: Ma, WenwuX <wenwux.ma@intel.com>
>> Sent: Wednesday, November 3, 2021 10:17 PM
>> To: dev@dpdk.org
>> Cc: maxime.coquelin@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>; Yigit,
>> Ferruh <ferruh.yigit@intel.com>; Jiang, Cheng1 <cheng1.jiang@intel.com>; Hu,
>> Jiayu <jiayu.hu@intel.com>; Yang, YvonneX <yvonnex.yang@intel.com>; Ma, WenwuX
>> <wenwux.ma@intel.com>; stable@dpdk.org
>> Subject: [PATCH v4] examples/vhost: fix failure to launch dpdk-vhost
>>
>> When the default max queue value of vhost is 128, dpdk-vhost will fail to
>> launch with a 40G i40e port due to the mbuf allocation of the port queue fails.
>> Therefore, we modify the default value of max queue from 128 to 512,
>> it will ensure that there are enough mbufs.
>>
>> Fixes: 4796ad63ba1f ("examples/vhost: import userspace vhost application")
>> Cc: stable@dpdk.org
> 
> When I was tracking the bad commit, I notice this change is on purpose to save hugepages:
> 
> commit f17eb179046962fdc29c3609b1c9bd46bfefa4f5
> Author: Bernard Iremonger <bernard.iremonger@intel.com>
> Date:   Thu Dec 10 15:49:17 2015 +0000
> 
>      examples/vhost: reduce number of hugepages needed
> 
>      Add #ifndef MAX_QUEUES to change MAX_QUEUES at compile time if needed.
>      Change MAX_QUEUES from 512 to 128 to reduce the number of hugepages
>      required by the vhost-switch program.
> 
>      To change MAX_QUEUES add '-D MAX_QUEUES=512' to the EXTRA_CFLAGS variable,
>      before building the application.
> 
>      Signed-off-by: Bernard Iremonger <bernard.iremonger@intel.com>
>      Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> 
> So as there's a way to solve the problem (although not perfect), I would suggest
> using the compiler flag to do tests with the specific NIC.
> 
> If no one has objection, let's drop the patch.

I agree, let's drop it.

Thanks,
Maxime
> Thanks,
> Chenbo
> 
>>
>> Signed-off-by: Wenwu Ma <wenwux.ma@intel.com>
>> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>   examples/vhost/main.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/examples/vhost/main.c b/examples/vhost/main.c
>> index bc3d71c898..36969a4de5 100644
>> --- a/examples/vhost/main.c
>> +++ b/examples/vhost/main.c
>> @@ -29,7 +29,7 @@
>>   #include "main.h"
>>
>>   #ifndef MAX_QUEUES
>> -#define MAX_QUEUES 128
>> +#define MAX_QUEUES 512
>>   #endif
>>
>>   /* the maximum number of external ports supported */
>> --
>> 2.25.1
>