2007-01-31 03:44:26

by Divy Le Ray

[permalink] [raw]
Subject: [PATCH 3/10] cxgb3 - remove SW Tx credits coalescing

From: Divy Le Ray <[email protected]>

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

Signed-off-by: Divy Le Ray <[email protected]>
---

drivers/net/cxgb3/sge.c | 75 +++++++++--------------------------------------
1 files changed, 14 insertions(+), 61 deletions(-)

diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index ccea06a..8b3c824 100644
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -1550,33 +1550,6 @@ static inline int rx_offload(struct t3cd
}

/**
- * 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,
* 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
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 adap
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 adap

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 adap
--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
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

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
}
} 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, s
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);