Commit 26b3871d authored by Divy Le Ray's avatar Divy Le Ray Committed by David S. Miller
Browse files

cxgb3: ring rx door bell less frequently 



Ring free lists door bell less frequently,
specifically every quarter of the active FL
size.

Signed-off-by: default avatarDivy Le Ray <divy@chelsio.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ff5e2b47

drivers/net/cxgb3/adapter.h

+1 −0
Original line number Diff line number Diff line
@@ -91,6 +91,7 @@ struct rx_sw_desc; 
struct sge_fl {                     /* SGE per free-buffer list state */

	unsigned int buf_size;      /* size of each Rx buffer */

	unsigned int credits;       /* # of available Rx buffers */

	unsigned int pend_cred;     /* new buffers since last FL DB ring */

	unsigned int size;          /* capacity of free list */

	unsigned int cidx;          /* consumer index */

	unsigned int pidx;          /* producer index */

drivers/net/cxgb3/sge.c

+24 −8
Original line number Diff line number Diff line
@@ -62,6 +62,10 @@ 


#define SGE_RX_DROP_THRES 16



/*

 * Max number of Rx buffers we replenish at a time.

 */

#define MAX_RX_REFILL 16U

/*

 * Period of the Tx buffer reclaim timer.  This timer does not need to run

 * frequently as Tx buffers are usually reclaimed by new Tx packets.
@@ -423,6 +427,14 @@ static int alloc_pg_chunk(struct sge_fl *q, struct rx_sw_desc *sd, gfp_t gfp, 
	return 0;

}



static inline void ring_fl_db(struct adapter *adap, struct sge_fl *q)

{

	if (q->pend_cred >= q->credits / 4) {

		q->pend_cred = 0;

		t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));

	}

}



/**

 *	refill_fl - refill an SGE free-buffer list

 *	@adapter: the adapter
@@ -478,19 +490,19 @@ nomem: q->alloc_failed++; 
			sd = q->sdesc;

			d = q->desc;

		}

		q->credits++;

		count++;

	}

	wmb();

	if (likely(count))

		t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));



	q->credits += count;

	q->pend_cred += count;

	ring_fl_db(adap, q);



	return count;

}



static inline void __refill_fl(struct adapter *adap, struct sge_fl *fl)

{

	refill_fl(adap, fl, min(16U, fl->size - fl->credits),

	refill_fl(adap, fl, min(MAX_RX_REFILL, fl->size - fl->credits),

		  GFP_ATOMIC | __GFP_COMP);

}
@@ -515,13 +527,15 @@ static void recycle_rx_buf(struct adapter *adap, struct sge_fl *q, 
	wmb();

	to->len_gen = cpu_to_be32(V_FLD_GEN1(q->gen));

	to->gen2 = cpu_to_be32(V_FLD_GEN2(q->gen));

	q->credits++;



	if (++q->pidx == q->size) {

		q->pidx = 0;

		q->gen ^= 1;

	}

	t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));



	q->credits++;

	q->pend_cred++;

	ring_fl_db(adap, q);

}



/**
@@ -732,7 +746,9 @@ static struct sk_buff *get_packet(struct adapter *adap, struct sge_fl *fl, 
		return skb;

	}



	if (unlikely(fl->credits < drop_thres))

	if (unlikely(fl->credits < drop_thres) &&

	    refill_fl(adap, fl, min(MAX_RX_REFILL, fl->size - fl->credits - 1),

		      GFP_ATOMIC | __GFP_COMP) == 0)

		goto recycle;



use_orig_buf: