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Re: [RFC PATCH 1/7] PF driver modified to enable HW filter support, changes works in backward compatibility mode Enable required things in Makefile Enable LZ4 dependecy inside config file

Started bySunil Kovvuri <sunil.kovvuri@gmail.com>
First post2016-12-21 14:10 +0100
Last post2016-12-27 05:30 +0100
Articles 3 — 2 participants

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  Re: [RFC PATCH 1/7] PF driver modified to enable HW filter support,  changes works in backward compatibility mode Enable required things in  Makefile Enable LZ4 dependecy inside config file Sunil Kovvuri <sunil.kovvuri@gmail.com> - 2016-12-21 14:10 +0100
    RE: [RFC PATCH 1/7] PF driver modified to enable HW filter support,  changes works in backward compatibility mode Enable required things in  Makefile Enable LZ4 dependecy inside config file "Koteshwar Rao, Satha" <Satha.Rao@cavium.com> - 2016-12-26 15:30 +0100
      Re: [RFC PATCH 1/7] PF driver modified to enable HW filter support,  changes works in backward compatibility mode Enable required things in  Makefile Enable LZ4 dependecy inside config file Sunil Kovvuri <sunil.kovvuri@gmail.com> - 2016-12-27 05:30 +0100

#1545754 — Re: [RFC PATCH 1/7] PF driver modified to enable HW filter support, changes works in backward compatibility mode Enable required things in Makefile Enable LZ4 dependecy inside config file

FromSunil Kovvuri <sunil.kovvuri@gmail.com>
Date2016-12-21 14:10 +0100
SubjectRe: [RFC PATCH 1/7] PF driver modified to enable HW filter support, changes works in backward compatibility mode Enable required things in Makefile Enable LZ4 dependecy inside config file
Message-ID<sQOOE-3SW-89@gated-at.bofh.it>
>
>  #define NIC_MAX_RSS_HASH_BITS          8
>  #define NIC_MAX_RSS_IDR_TBL_SIZE       (1 << NIC_MAX_RSS_HASH_BITS)
> +#define NIC_TNS_RSS_IDR_TBL_SIZE       5

So you want to use only 5 queues per VF when TNS is enabled, is it ??
There are 4096 RSS indices in total, for each VF you can use max 32.
I guess you wanted to set no of hash bits to 5 instead of table size.

>  #define RSS_HASH_KEY_SIZE              5 /* 320 bit key */
>
>  struct nicvf_rss_info {
> @@ -255,74 +258,6 @@ struct nicvf_drv_stats {
>         struct u64_stats_sync   syncp;
>  };
>
> -struct nicvf {
> -       struct nicvf            *pnicvf;
> -       struct net_device       *netdev;
> -       struct pci_dev          *pdev;
> -       void __iomem            *reg_base;

Didn't get why you moved this structure to the end of file.
Looks like an unnecessary modification.


> +static unsigned int num_vfs;
> +module_param(num_vfs, uint, 0644);
> +MODULE_PARM_DESC(num_vfs, "Non zero positive value, specifies number of VF's per physical port");

So what if driver is built-in instead of module, I can't use TNS is it ?

>
> +/* Set RBDR Backpressure (RBDR_BP) and CQ backpressure (CQ_BP) of vnic queues
> + * to 129 each

Why 129 ??
RBDR minimum size is 8K buffers, why you want to assert BP when still
~4K buffers
are available. Isn't 4K a huge number to start asserting backpressure ?

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#1547325

From"Koteshwar Rao, Satha" <Satha.Rao@cavium.com>
Date2016-12-26 15:30 +0100
Message-ID<sSErL-5SM-13@gated-at.bofh.it>
In reply to#1545754
Responses inline

Thanks,
Satha

-----Original Message-----
From: Sunil Kovvuri [mailto:sunil.kovvuri@gmail.com] 
Sent: Wednesday, December 21, 2016 5:05 AM
To: Koteshwar Rao, Satha
Cc: LKML; Goutham, Sunil; Robert Richter; David S. Miller; Daney, David; Vatsavayi, Raghu; Chickles, Derek; Romanov, Philip; Linux Netdev List; LAKML
Subject: Re: [RFC PATCH 1/7] PF driver modified to enable HW filter support, changes works in backward compatibility mode Enable required things in Makefile Enable LZ4 dependecy inside config file

>
>  #define NIC_MAX_RSS_HASH_BITS          8
>  #define NIC_MAX_RSS_IDR_TBL_SIZE       (1 << NIC_MAX_RSS_HASH_BITS)
> +#define NIC_TNS_RSS_IDR_TBL_SIZE       5

So you want to use only 5 queues per VF when TNS is enabled, is it ??
There are 4096 RSS indices in total, for each VF you can use max 32.
I guess you wanted to set no of hash bits to 5 instead of table size.

SATHA>>> We enabled 8 queues for VF. Yes Macro name misleads it has to be hash bits, will change this in next version

>  #define RSS_HASH_KEY_SIZE              5 /* 320 bit key */
>
>  struct nicvf_rss_info {
> @@ -255,74 +258,6 @@ struct nicvf_drv_stats {
>         struct u64_stats_sync   syncp;
>  };
>
> -struct nicvf {
> -       struct nicvf            *pnicvf;
> -       struct net_device       *netdev;
> -       struct pci_dev          *pdev;
> -       void __iomem            *reg_base;

Didn't get why you moved this structure to the end of file.
Looks like an unnecessary modification.
SATHA>>> Previously we have some dependency, we look into this, and address in next verison

> +static unsigned int num_vfs;
> +module_param(num_vfs, uint, 0644);
> +MODULE_PARM_DESC(num_vfs, "Non zero positive value, specifies number 
> +of VF's per physical port");

So what if driver is built-in instead of module, I can't use TNS is it ?
SATHA>>> Still you can enable this special features by passing boot argument "nicpf.num_vfs=X"

>
> +/* Set RBDR Backpressure (RBDR_BP) and CQ backpressure (CQ_BP) of 
> +vnic queues
> + * to 129 each

Why 129 ??
RBDR minimum size is 8K buffers, why you want to assert BP when still ~4K buffers are available. Isn't 4K a huge number to start asserting backpressure ?
SATHA>>> As CQ count was 4K entries, I used same BP value for both, will address this in next version

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#1547491

FromSunil Kovvuri <sunil.kovvuri@gmail.com>
Date2016-12-27 05:30 +0100
Message-ID<sSRyG-5IB-9@gated-at.bofh.it>
In reply to#1547325
>>  #define NIC_MAX_RSS_HASH_BITS          8
>>  #define NIC_MAX_RSS_IDR_TBL_SIZE       (1 << NIC_MAX_RSS_HASH_BITS)
>> +#define NIC_TNS_RSS_IDR_TBL_SIZE       5
>
> So you want to use only 5 queues per VF when TNS is enabled, is it ??
> There are 4096 RSS indices in total, for each VF you can use max 32.
> I guess you wanted to set no of hash bits to 5 instead of table size.
>
> SATHA>>> We enabled 8 queues for VF. Yes Macro name misleads it has to be hash bits, will change this in next version

No, I am not referring to any discrepancy in naming the macro.
If you check your code

- hw->rss_ind_tbl_size = NIC_MAX_RSS_IDR_TBL_SIZE;
+ hw->rss_ind_tbl_size = veb_enabled ? NIC_TNS_RSS_IDR_TBL_SIZE :
+     NIC_MAX_RSS_IDR_TBL_SIZE;

You are setting RSS table size to 5, i.e RSS hash bits will be set to 2.
Hence only 4 queues (not even 5 as i mentioned earlier). Please check
'nicvf_rss_init' you will understand what i am saying.
Have you tested and observed pkts in all 8 queues ?

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