ixgbe: further flow director performance optimizations

This change adds a compressed input type for atr signature hash
computation.  It also drops the use of the set functions when setting up
the ATR input since we can then directly setup the hash input as two dwords
that can be stored and passed as registers.

With these changes the cost of computing the has is low enough that we can
perform a hash computation on each TCP SYN flagged packet allowing us to
drop the number of flow director misses considerably in tests such as
netperf TCP_CRR.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 99 insertions, 13 deletions

diff --git a/drivers/net/ixgbe/ixgbe_82599.c b/drivers/net/ixgbe/ixgbe_82599.c
index 40aa3c2..d41931f 100644
--- a/drivers/net/ixgbe/ixgbe_82599.c
+++ b/drivers/net/ixgbe/ixgbe_82599.c
@@ -1331,6 +1331,96 @@ static u32 ixgbe_atr_compute_hash_82599(union ixgbe_atr_input *atr_input,
 	return hash_result & IXGBE_ATR_HASH_MASK;
 }
 
+/*
+ * These defines allow us to quickly generate all of the necessary instructions
+ * in the function below by simply calling out IXGBE_COMPUTE_SIG_HASH_ITERATION
+ * for values 0 through 15
+ */
+#define IXGBE_ATR_COMMON_HASH_KEY \
+		(IXGBE_ATR_BUCKET_HASH_KEY & IXGBE_ATR_SIGNATURE_HASH_KEY)
+#define IXGBE_COMPUTE_SIG_HASH_ITERATION(_n) \
+do { \
+	u32 n = (_n); \
+	if (IXGBE_ATR_COMMON_HASH_KEY & (0x01 << n)) \
+		common_hash ^= lo_hash_dword >> n; \
+	else if (IXGBE_ATR_BUCKET_HASH_KEY & (0x01 << n)) \
+		bucket_hash ^= lo_hash_dword >> n; \
+	else if (IXGBE_ATR_SIGNATURE_HASH_KEY & (0x01 << n)) \
+		sig_hash ^= lo_hash_dword << (16 - n); \
+	if (IXGBE_ATR_COMMON_HASH_KEY & (0x01 << (n + 16))) \
+		common_hash ^= hi_hash_dword >> n; \
+	else if (IXGBE_ATR_BUCKET_HASH_KEY & (0x01 << (n + 16))) \
+		bucket_hash ^= hi_hash_dword >> n; \
+	else if (IXGBE_ATR_SIGNATURE_HASH_KEY & (0x01 << (n + 16))) \
+		sig_hash ^= hi_hash_dword << (16 - n); \
+} while (0);
+
+/**
+ *  ixgbe_atr_compute_sig_hash_82599 - Compute the signature hash
+ *  @stream: input bitstream to compute the hash on
+ *
+ *  This function is almost identical to the function above but contains
+ *  several optomizations such as unwinding all of the loops, letting the
+ *  compiler work out all of the conditional ifs since the keys are static
+ *  defines, and computing two keys at once since the hashed dword stream
+ *  will be the same for both keys.
+ **/
+static u32 ixgbe_atr_compute_sig_hash_82599(union ixgbe_atr_hash_dword input,
+					    union ixgbe_atr_hash_dword common)
+{
+	u32 hi_hash_dword, lo_hash_dword, flow_vm_vlan;
+	u32 sig_hash = 0, bucket_hash = 0, common_hash = 0;
+
+	/* record the flow_vm_vlan bits as they are a key part to the hash */
+	flow_vm_vlan = ntohl(input.dword);
+
+	/* generate common hash dword */
+	hi_hash_dword = ntohl(common.dword);
+
+	/* low dword is word swapped version of common */
+	lo_hash_dword = (hi_hash_dword >> 16) | (hi_hash_dword << 16);
+
+	/* apply flow ID/VM pool/VLAN ID bits to hash words */
+	hi_hash_dword ^= flow_vm_vlan ^ (flow_vm_vlan >> 16);
+
+	/* Process bits 0 and 16 */
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(0);
+
+	/*
+	 * apply flow ID/VM pool/VLAN ID bits to lo hash dword, we had to
+	 * delay this because bit 0 of the stream should not be processed
+	 * so we do not add the vlan until after bit 0 was processed
+	 */
+	lo_hash_dword ^= flow_vm_vlan ^ (flow_vm_vlan << 16);
+
+	/* Process remaining 30 bit of the key */
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(1);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(2);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(3);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(4);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(5);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(6);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(7);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(8);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(9);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(10);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(11);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(12);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(13);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(14);
+	IXGBE_COMPUTE_SIG_HASH_ITERATION(15);
+
+	/* combine common_hash result with signature and bucket hashes */
+	bucket_hash ^= common_hash;
+	bucket_hash &= IXGBE_ATR_HASH_MASK;
+
+	sig_hash ^= common_hash << 16;
+	sig_hash &= IXGBE_ATR_HASH_MASK << 16;
+
+	/* return completed signature hash */
+	return sig_hash ^ bucket_hash;
+}
+
 /**
  *  ixgbe_atr_set_vlan_id_82599 - Sets the VLAN id in the ATR input stream
  *  @input: input stream to modify
@@ -1539,22 +1629,23 @@ static s32 ixgbe_atr_get_l4type_82599(union ixgbe_atr_input *input,
 /**
  *  ixgbe_atr_add_signature_filter_82599 - Adds a signature hash filter
  *  @hw: pointer to hardware structure
- *  @stream: input bitstream
+ *  @input: unique input dword
+ *  @common: compressed common input dword
  *  @queue: queue index to direct traffic to
  **/
 s32 ixgbe_fdir_add_signature_filter_82599(struct ixgbe_hw *hw,
-                                          union ixgbe_atr_input *input,
+                                          union ixgbe_atr_hash_dword input,
+                                          union ixgbe_atr_hash_dword common,
                                           u8 queue)
 {
 	u64  fdirhashcmd;
 	u32  fdircmd;
-	u32  bucket_hash, sig_hash;
 
 	/*
 	 * Get the flow_type in order to program FDIRCMD properly
 	 * lowest 2 bits are FDIRCMD.L4TYPE, third lowest bit is FDIRCMD.IPV6
 	 */
-	switch (input->formatted.flow_type) {
+	switch (input.formatted.flow_type) {
 	case IXGBE_ATR_FLOW_TYPE_TCPV4:
 	case IXGBE_ATR_FLOW_TYPE_UDPV4:
 	case IXGBE_ATR_FLOW_TYPE_SCTPV4:
@@ -1570,7 +1661,7 @@ s32 ixgbe_fdir_add_signature_filter_82599(struct ixgbe_hw *hw,
 	/* configure FDIRCMD register */
 	fdircmd = IXGBE_FDIRCMD_CMD_ADD_FLOW | IXGBE_FDIRCMD_FILTER_UPDATE |
 	          IXGBE_FDIRCMD_LAST | IXGBE_FDIRCMD_QUEUE_EN;
-	fdircmd |= input->formatted.flow_type << IXGBE_FDIRCMD_FLOW_TYPE_SHIFT;
+	fdircmd |= input.formatted.flow_type << IXGBE_FDIRCMD_FLOW_TYPE_SHIFT;
 	fdircmd |= (u32)queue << IXGBE_FDIRCMD_RX_QUEUE_SHIFT;
 
 	/*
@@ -1578,17 +1669,12 @@ s32 ixgbe_fdir_add_signature_filter_82599(struct ixgbe_hw *hw,
 	 * is for FDIRCMD.  Then do a 64-bit register write from FDIRHASH.
 	 */
 	fdirhashcmd = (u64)fdircmd << 32;
-
-	sig_hash = ixgbe_atr_compute_hash_82599(input,
-	                                        IXGBE_ATR_SIGNATURE_HASH_KEY);
-	fdirhashcmd |= sig_hash << IXGBE_FDIRHASH_SIG_SW_INDEX_SHIFT;
-
-	bucket_hash = ixgbe_atr_compute_hash_82599(input,
-	                                           IXGBE_ATR_BUCKET_HASH_KEY);
-	fdirhashcmd |= bucket_hash;
+	fdirhashcmd |= ixgbe_atr_compute_sig_hash_82599(input, common);
 
 	IXGBE_WRITE_REG64(hw, IXGBE_FDIRHASH, fdirhashcmd);
 
+	hw_dbg(hw, "Tx Queue=%x hash=%x\n", queue, (u32)fdirhashcmd);
+
 	return 0;
 }