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Commit 6195c71d authored by Divy Le Ray's avatar Divy Le Ray Committed by Jeff Garzik
Browse files

cxgb3 - remove SW Tx credits coalescing 



Remove tx credit coalescing done in SW.
The HW is caring care of it already.

Signed-off-by: default avatarDivy Le Ray <divy@chelsio.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 14ab9892

drivers/net/cxgb3/sge.c

+14 −61
Original line number Diff line number Diff line
@@ -1549,33 +1549,6 @@ static inline int rx_offload(struct t3cdev *tdev, struct sge_rspq *rq, 
	return gather_idx;

}



/**

 *	update_tx_completed - update the number of processed Tx descriptors

 *	@qs: the queue set to update

 *	@idx: which Tx queue within the set to update

 *	@credits: number of new processed descriptors

 *	@tx_completed: accumulates credits for the queues

 *

 *	Updates the number of completed Tx descriptors for a queue set's Tx

 *	queue.  On UP systems we updated the information immediately but on

 *	MP we accumulate the credits locally and update the Tx queue when we

 *	reach a threshold to avoid cache-line bouncing.

 */

static inline void update_tx_completed(struct sge_qset *qs, int idx,

				       unsigned int credits,

				       unsigned int tx_completed[])

{

#ifdef CONFIG_SMP

	tx_completed[idx] += credits;

	if (tx_completed[idx] > 32) {

		qs->txq[idx].processed += tx_completed[idx];

		tx_completed[idx] = 0;

	}

#else

	qs->txq[idx].processed += credits;

#endif

}



/**

 *	restart_tx - check whether to restart suspended Tx queues

 *	@qs: the queue set to resume
@@ -1656,13 +1629,12 @@ static void rx_eth(struct adapter *adap, struct sge_rspq *rq, 
 *	handle_rsp_cntrl_info - handles control information in a response

 *	@qs: the queue set corresponding to the response

 *	@flags: the response control flags

 *	@tx_completed: accumulates completion credits for the Tx queues

 *

 *	Handles the control information of an SGE response, such as GTS

 *	indications and completion credits for the queue set's Tx queues.

 *	HW coalesces credits, we don't do any extra SW coalescing.

 */

static inline void handle_rsp_cntrl_info(struct sge_qset *qs, u32 flags,

					 unsigned int tx_completed[])

static inline void handle_rsp_cntrl_info(struct sge_qset *qs, u32 flags)

{

	unsigned int credits;
@@ -1671,37 +1643,21 @@ static inline void handle_rsp_cntrl_info(struct sge_qset *qs, u32 flags, 
		clear_bit(TXQ_RUNNING, &qs->txq[TXQ_ETH].flags);

#endif



	/* ETH credits are already coalesced, return them immediately. */

	credits = G_RSPD_TXQ0_CR(flags);

	if (credits)

		qs->txq[TXQ_ETH].processed += credits;



	credits = G_RSPD_TXQ2_CR(flags);

	if (credits)

		qs->txq[TXQ_CTRL].processed += credits;



# if USE_GTS

	if (flags & F_RSPD_TXQ1_GTS)

		clear_bit(TXQ_RUNNING, &qs->txq[TXQ_OFLD].flags);

# endif

	update_tx_completed(qs, TXQ_OFLD, G_RSPD_TXQ1_CR(flags), tx_completed);

	update_tx_completed(qs, TXQ_CTRL, G_RSPD_TXQ2_CR(flags), tx_completed);

}



/**

 *	flush_tx_completed - returns accumulated Tx completions to Tx queues

 *	@qs: the queue set to update

 *	@tx_completed: pending completion credits to return to Tx queues

 *

 *	Updates the number of completed Tx descriptors for a queue set's Tx

 *	queues with the credits pending in @tx_completed.  This does something

 *	only on MP systems as on UP systems we return the credits immediately.

 */

static inline void flush_tx_completed(struct sge_qset *qs,

				      unsigned int tx_completed[])

{

#if defined(CONFIG_SMP)

	if (tx_completed[TXQ_OFLD])

		qs->txq[TXQ_OFLD].processed += tx_completed[TXQ_OFLD];

	if (tx_completed[TXQ_CTRL])

		qs->txq[TXQ_CTRL].processed += tx_completed[TXQ_CTRL];

#endif

	credits = G_RSPD_TXQ1_CR(flags);

	if (credits)

		qs->txq[TXQ_OFLD].processed += credits;

}



/**
@@ -1784,7 +1740,7 @@ static int process_responses(struct adapter *adap, struct sge_qset *qs, 
	struct sge_rspq *q = &qs->rspq;

	struct rsp_desc *r = &q->desc[q->cidx];

	int budget_left = budget;

	unsigned int sleeping = 0, tx_completed[3] = { 0, 0, 0 };

	unsigned int sleeping = 0;

	struct sk_buff *offload_skbs[RX_BUNDLE_SIZE];

	int ngathered = 0;
@@ -1837,7 +1793,7 @@ static int process_responses(struct adapter *adap, struct sge_qset *qs, 


		if (flags & RSPD_CTRL_MASK) {

			sleeping |= flags & RSPD_GTS_MASK;

			handle_rsp_cntrl_info(qs, flags, tx_completed);

			handle_rsp_cntrl_info(qs, flags);

		}



		r++;
@@ -1868,7 +1824,6 @@ static int process_responses(struct adapter *adap, struct sge_qset *qs, 
		--budget_left;

	}



	flush_tx_completed(qs, tx_completed);

	deliver_partial_bundle(&adap->tdev, q, offload_skbs, ngathered);

	if (sleeping)

		check_ring_db(adap, qs, sleeping);
@@ -1953,7 +1908,7 @@ static int process_pure_responses(struct adapter *adap, struct sge_qset *qs, 
				  struct rsp_desc *r)

{

	struct sge_rspq *q = &qs->rspq;

	unsigned int sleeping = 0, tx_completed[3] = { 0, 0, 0 };

	unsigned int sleeping = 0;



	do {

		u32 flags = ntohl(r->flags);
@@ -1968,7 +1923,7 @@ static int process_pure_responses(struct adapter *adap, struct sge_qset *qs, 


		if (flags & RSPD_CTRL_MASK) {

			sleeping |= flags & RSPD_GTS_MASK;

			handle_rsp_cntrl_info(qs, flags, tx_completed);

			handle_rsp_cntrl_info(qs, flags);

		}



		q->pure_rsps++;
@@ -1978,8 +1933,6 @@ static int process_pure_responses(struct adapter *adap, struct sge_qset *qs, 
		}

	} while (is_new_response(r, q) && is_pure_response(r));



	flush_tx_completed(qs, tx_completed);



	if (sleeping)

		check_ring_db(adap, qs, sleeping);
@@ -2630,7 +2583,7 @@ void t3_sge_init(struct adapter *adap, struct sge_params *p) 
		     V_LORCQDRBTHRSH(512));

	t3_write_reg(adap, A_SG_TIMER_TICK, core_ticks_per_usec(adap) / 10);

	t3_write_reg(adap, A_SG_CMDQ_CREDIT_TH, V_THRESHOLD(32) |

		     V_TIMEOUT(100 * core_ticks_per_usec(adap)));

		     V_TIMEOUT(200 * core_ticks_per_usec(adap)));

	t3_write_reg(adap, A_SG_HI_DRB_HI_THRSH, 1000);

	t3_write_reg(adap, A_SG_HI_DRB_LO_THRSH, 256);

	t3_write_reg(adap, A_SG_LO_DRB_HI_THRSH, 1000);