Subject: Re: [Intel-wired-lan] [PATCH net-next v1 1/2] ixgbe: Refactor the RSS configuration code.

From: Vlad Zolotarov <[email-masked]>
Date: Thu, 26 Mar 2015 22:55:15 +0200

On 03/26/15 22:20, Tantilov, Emil S wrote:
>> -----Original Message-----
>> From: Intel-wired-lan [mailto:[email-masked]] On Behalf Of Vlad Zolotarov
>> Sent: Thursday, March 26, 2015 10:57 AM
>> Subject: [Intel-wired-lan] [PATCH net-next v1 1/2] ixgbe: Refactor the RSS configuration code.
>>
>> This patch is a preparation for enablement of ethtool RSS indirection table
>> and hash key querying. We don't want to read registers every time the RSS info
>> is queried. Therefore we will store its current content in the
>> arrays in the adapter struct and will read it from there (instead of from
>> registers) when requested.
>>
>> Will change the code that writes the indirection table and hash key into the HW registers
>> to take its content from these arrays. This will also simplify the indirection
>> table updating ethtool callback implementation in the future.
>>
>> Signed-off-by: Vlad Zolotarov <[email-masked]>
>> ---
>> drivers/net/ethernet/intel/ixgbe/ixgbe.h      |   2 +
>> drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 143 ++++++++++++++++++--------
>> drivers/net/ethernet/intel/ixgbe/ixgbe_type.h |   7 ++
>> 3 files changed, 109 insertions(+), 43 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>> index 5e44e48..402d182 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>> @@ -766,6 +766,8 @@ struct ixgbe_adapter {
>>
>> 	u8 default_up;
>> 	unsigned long fwd_bitmask; /* Bitmask indicating in use pools */
>> +	u8 rss_indir_tbl[IXGBE_MAX_RETA_ENTRIES];
>> +	u32 rss_key[IXGBE_RSS_KEY_SIZE / sizeof(u32)];
>> };
>>
>> static inline u8 ixgbe_max_rss_indices(struct ixgbe_adapter *adapter)
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>> index 8853d52..e3de0c9 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>> @@ -3228,51 +3228,54 @@ static void ixgbe_configure_srrctl(struct ixgbe_adapter *adapter,
>> 	IXGBE_WRITE_REG(hw, IXGBE_SRRCTL(reg_idx), srrctl);
>> }
>>
>> -static void ixgbe_setup_reta(struct ixgbe_adapter *adapter, const u32 *seed)
>> +/**
>> + * Return a number of entries in the RSS indirection table
> The preferred style for multiline comments is to not start with an empty "/*" checkpatch would generally
> catch those.

It's not a multi-line comment but a function description and its styling 
is perfectly fine.

>
>> + *
>> + * @adapter: device handle
>> + *
>> + *  - 82598/82599/X540:     128
>> + *  - X550(non-SRIOV mode): 512
>> + *  - X550(SRIOV mode):     64
>> + */
>> +static u32 ixgbe_rss_indir_tbl_entries(struct ixgbe_adapter *adapter)
>> +{
>> +	if (adapter->hw.mac.type < ixgbe_mac_X550)
>> +		return 128;
>> +	else if (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED)
>> +		return 64;
>> +	else
>> +		return 512;
>> +}
>> +
>> +/**
>> + * Write the RETA table to HW
>> + *
>> + * @adapter: device handle
>> + *
>> + * Write the RSS redirection table stored in adapter.rss_indir_tbl[] to HW.
>> + */
>> +static void ixgbe_store_reta(struct ixgbe_adapter *adapter)
> What is the point of having separate functions for writing the registers? Unless you intend to use
> them in other parts of the code, those can be folded inside ixgbe_setupvf/reta().

The one that is going to implement the ethtool -X is going to use it. ;)

>
>> {
>> +	u32 i, reta_entries = ixgbe_rss_indir_tbl_entries(adapter);
>> 	struct ixgbe_hw *hw = &adapter->hw;
>> 	u32 reta = 0;
>> -	int i, j;
>> -	int reta_entries = 128;
>> -	u16 rss_i = adapter->ring_feature[RING_F_RSS].indices;
>> 	int indices_multi;
>> -
>> -	/*
>> -	 * Program table for at least 2 queues w/ SR-IOV so that VFs can
>> -	 * make full use of any rings they may have.  We will use the
>> -	 * PSRTYPE register to control how many rings we use within the PF.
>> -	 */
>> -	if ((adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) && (rss_i < 2))
>> -		rss_i = 2;
>> -
>> -	/* Fill out hash function seeds */
>> -	for (i = 0; i < 10; i++)
>> -		IXGBE_WRITE_REG(hw, IXGBE_RSSRK(i), seed[i]);
>> +	u8 *indir_tbl = adapter->rss_indir_tbl;
>>
>> 	/* Fill out the redirection table as follows:
>> -	 * 82598: 128 (8 bit wide) entries containing pair of 4 bit RSS indices
>> -	 * 82599/X540: 128 (8 bit wide) entries containing 4 bit RSS index
>> -	 * X550: 512 (8 bit wide) entries containing 6 bit RSS index
>> +	 *  - 82598:      8 bit wide entries containing pair of 4 bit RSS
>> +	 *    indices.
>> +	 *  - 82599/X540: 8 bit wide entries containing 4 bit RSS index
>> +	 *  - X550:       8 bit wide entries containing 6 bit RSS index
>> 	 */
>> 	if (adapter->hw.mac.type == ixgbe_mac_82598EB)
>> 		indices_multi = 0x11;
>> 	else
>> 		indices_multi = 0x1;
>>
>> -	switch (adapter->hw.mac.type) {
>> -	case ixgbe_mac_X550:
>> -	case ixgbe_mac_X550EM_x:
>> -		if (!(adapter->flags & IXGBE_FLAG_SRIOV_ENABLED))
>> -			reta_entries = 512;
>> -	default:
>> -		break;
>> -	}
>> -
>> -	/* Fill out redirection table */
>> -	for (i = 0, j = 0; i < reta_entries; i++, j++) {
>> -		if (j == rss_i)
>> -			j = 0;
>> -		reta = (reta << 8) | (j * indices_multi);
>> +	/* Write redirection table to HW */
>> +	for (i = 0; i < reta_entries; i++) {
>> +		reta = (reta << 8) | (indices_multi * indir_tbl[i]);
>> 		if ((i & 3) == 3) {
>> 			if (i < 128)
>> 				IXGBE_WRITE_REG(hw, IXGBE_RETA(i >> 2), reta);
>> @@ -3283,34 +3286,88 @@ static void ixgbe_setup_reta(struct ixgbe_adapter *adapter, const u32 *seed)
>> 	}
>> }
>>
>> -static void ixgbe_setup_vfreta(struct ixgbe_adapter *adapter, const u32 *seed)
>> +/**
>> + * Write the RETA table to HW (for x550 devices in SRIOV mode)
>> + *
>> + * @adapter: device handle
>> + *
>> + * Write the RSS redirection table stored in adapter.rss_indir_tbl[] to HW.
>> + */
>> +static void ixgbe_store_vfreta(struct ixgbe_adapter *adapter)
>> {
>> +	u32 i, reta_entries = ixgbe_rss_indir_tbl_entries(adapter);
>> 	struct ixgbe_hw *hw = &adapter->hw;
>> 	u32 vfreta = 0;
>> +	unsigned int pf_pool = adapter->num_vfs;
>> +
>> +	/* Write redirection table to HW */
>> +	for (i = 0; i < reta_entries; i++) {
>> +		vfreta = (vfreta << 8) | adapter->rss_indir_tbl[i];
>> +		if ((i & 3) == 3)
>> +			IXGBE_WRITE_REG(hw, IXGBE_PFVFRETA(i >> 2, pf_pool),
>> +					vfreta);
>> +	}
>> +}
>> +
>> +static void ixgbe_setup_reta(struct ixgbe_adapter *adapter)
>> +{
>> +	struct ixgbe_hw *hw = &adapter->hw;
>> +	u32 i, j;
>> +	u32 reta_entries = ixgbe_rss_indir_tbl_entries(adapter);
>> +	u16 rss_i = adapter->ring_feature[RING_F_RSS].indices;
>> +
>> +	/*
>> +	 * Program table for at least 2 queues w/ SR-IOV so that VFs can
>> +	 * make full use of any rings they may have.  We will use the
>> +	 * PSRTYPE register to control how many rings we use within the PF.
>> +	 */
>> +	if ((adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) && (rss_i < 2))
>> +		rss_i = 2;
>> +
>> +	/* Fill out hash function seeds */
>> +	for (i = 0; i < 10; i++)
>> +		IXGBE_WRITE_REG(hw, IXGBE_RSSRK(i), adapter->rss_key[i]);
>> +
>> +	/* Fill out redirection table */
>> +	memset(adapter->rss_indir_tbl, 0, sizeof(adapter->rss_indir_tbl));
>> +
>> +	for (i = 0, j = 0; i < reta_entries; i++, j++) {
>> +		if (j == rss_i)
>> +			j = 0;
>> +
>> +		adapter->rss_indir_tbl[i] = j;
>> +	}
>> +
>> +	ixgbe_store_reta(adapter);
>> +}
>> +
>> +static void ixgbe_setup_vfreta(struct ixgbe_adapter *adapter)
>> +{
>> +	struct ixgbe_hw *hw = &adapter->hw;
>> 	u16 rss_i = adapter->ring_feature[RING_F_RSS].indices;
>> 	unsigned int pf_pool = adapter->num_vfs;
>> 	int i, j;
>>
>> 	/* Fill out hash function seeds */
>> 	for (i = 0; i < 10; i++)
>> -		IXGBE_WRITE_REG(hw, IXGBE_PFVFRSSRK(i, pf_pool), seed[i]);
>> +		IXGBE_WRITE_REG(hw, IXGBE_PFVFRSSRK(i, pf_pool),
>> +				adapter->rss_key[i]);
>>
>> 	/* Fill out the redirection table */
>> 	for (i = 0, j = 0; i < 64; i++, j++) {
>> 		if (j == rss_i)
>> 			j = 0;
>> -		vfreta = (vfreta << 8) | j;
>> -		if ((i & 3) == 3)
>> -			IXGBE_WRITE_REG(hw, IXGBE_PFVFRETA(i >> 2, pf_pool),
>> -					vfreta);
>> +
>> +		adapter->rss_indir_tbl[i] = j;
>> 	}
>> +
>> +	ixgbe_store_vfreta(adapter);
>> }
>>
>> static void ixgbe_setup_mrqc(struct ixgbe_adapter *adapter)
>> {
>> 	struct ixgbe_hw *hw = &adapter->hw;
>> 	u32 mrqc = 0, rss_field = 0, vfmrqc = 0;
>> -	u32 rss_key[10];
>> 	u32 rxcsum;
>>
>> 	/* Disable indicating checksum in descriptor, enables RSS hash */
>> @@ -3354,7 +3411,7 @@ static void ixgbe_setup_mrqc(struct ixgbe_adapter *adapter)
>> 	if (adapter->flags2 & IXGBE_FLAG2_RSS_FIELD_IPV6_UDP)
>> 		rss_field |= IXGBE_MRQC_RSS_FIELD_IPV6_UDP;
>>
>> -	netdev_rss_key_fill(rss_key, sizeof(rss_key));
>> +	netdev_rss_key_fill(adapter->rss_key, sizeof(adapter->rss_key));
>> 	if ((hw->mac.type >= ixgbe_mac_X550) &&
>> 	    (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED)) {
>> 		unsigned int pf_pool = adapter->num_vfs;
>> @@ -3364,12 +3421,12 @@ static void ixgbe_setup_mrqc(struct ixgbe_adapter *adapter)
>> 		IXGBE_WRITE_REG(hw, IXGBE_MRQC, mrqc);
>>
>> 		/* Setup RSS through the VF registers */
>> -		ixgbe_setup_vfreta(adapter, rss_key);
>> +		ixgbe_setup_vfreta(adapter);
>> 		vfmrqc = IXGBE_MRQC_RSSEN;
>> 		vfmrqc |= rss_field;
>> 		IXGBE_WRITE_REG(hw, IXGBE_PFVFMRQC(pf_pool), vfmrqc);
>> 	} else {
>> -		ixgbe_setup_reta(adapter, rss_key);
>> +		ixgbe_setup_reta(adapter);
>> 		mrqc |= rss_field;
>> 		IXGBE_WRITE_REG(hw, IXGBE_MRQC, mrqc);
>> 	}
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
>> index c3ddc94..0c671b1 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
>> @@ -311,6 +311,13 @@ struct ixgbe_thermal_sensor_data {
>> #define IXGBE_ERETA(_i)	(0x0EE80 + ((_i) * 4))  /* 96 of these (0-95) */
>> #define IXGBE_RSSRK(_i) (0x05C80 + ((_i) * 4))  /* 10 of these (0-9) */
>>
>> +/* maximum number of RETA entries among all devices supported by ixgbe
>> + * driver: currently it's x550 device in non-SRIOV mode
>> + */
>> +#define IXGBE_MAX_RETA_ENTRIES 512
>> +
>> +#define IXGBE_RSS_KEY_SIZE     40  /* size of RSS Hash Key in bytes */
>> +
> These defines should be in ixgbe.h

Why? These are HW related macros and IMHO they belong to ixgbe_type.h 
with other HW related macros and not to ixgbe.h where SW related macros are.

>
>> /* Registers for setting up RSS on X550 with SRIOV
>>   * _p - pool number (0..63)
>>   * _i - index (0..10 for PFVFRSSRK, 0..15 for PFVFRETA)
> Thanks,
> Emil
>