From: Roland Dreier <roland@topspin.com>
From: "Michael S. Tsirkin" <mst@mellanox.co.il>
Event queue handling performance improvements:
- Only calculate EQ entry address once, and don't truncate the
consumer index until we really need to.
- Only read ECR once. If a new event occurs while we're in the
interrupt handler, we'll get another interrupt anyway, since we
only clear events once.
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/infiniband/hw/mthca/mthca_eq.c | 44 ++++++++++---------
25-akpm/drivers/infiniband/hw/mthca/mthca_provider.h | 2
2 files changed, 25 insertions(+), 21 deletions(-)
diff -puN drivers/infiniband/hw/mthca/mthca_eq.c~infiniband-mthca-optimize-event-queue-handling drivers/infiniband/hw/mthca/mthca_eq.c
--- 25/drivers/infiniband/hw/mthca/mthca_eq.c~infiniband-mthca-optimize-event-queue-handling 2005-01-23 22:25:01.247412536 -0800
+++ 25-akpm/drivers/infiniband/hw/mthca/mthca_eq.c 2005-01-23 22:25:01.254411472 -0800
@@ -164,12 +164,12 @@ static inline u64 async_mask(struct mthc
MTHCA_ASYNC_EVENT_MASK;
}
-static inline void set_eq_ci(struct mthca_dev *dev, int eqn, int ci)
+static inline void set_eq_ci(struct mthca_dev *dev, struct mthca_eq *eq, u32 ci)
{
u32 doorbell[2];
- doorbell[0] = cpu_to_be32(MTHCA_EQ_DB_SET_CI | eqn);
- doorbell[1] = cpu_to_be32(ci);
+ doorbell[0] = cpu_to_be32(MTHCA_EQ_DB_SET_CI | eq->eqn);
+ doorbell[1] = cpu_to_be32(ci & (eq->nent - 1));
mthca_write64(doorbell,
dev->kar + MTHCA_EQ_DOORBELL,
@@ -200,21 +200,22 @@ static inline void disarm_cq(struct mthc
MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
}
-static inline struct mthca_eqe *get_eqe(struct mthca_eq *eq, int entry)
+static inline struct mthca_eqe *get_eqe(struct mthca_eq *eq, u32 entry)
{
- return eq->page_list[entry * MTHCA_EQ_ENTRY_SIZE / PAGE_SIZE].buf
- + (entry * MTHCA_EQ_ENTRY_SIZE) % PAGE_SIZE;
+ unsigned long off = (entry & (eq->nent - 1)) * MTHCA_EQ_ENTRY_SIZE;
+ return eq->page_list[off / PAGE_SIZE].buf + off % PAGE_SIZE;
}
-static inline int next_eqe_sw(struct mthca_eq *eq)
+static inline struct mthca_eqe* next_eqe_sw(struct mthca_eq *eq)
{
- return !(MTHCA_EQ_ENTRY_OWNER_HW &
- get_eqe(eq, eq->cons_index)->owner);
+ struct mthca_eqe* eqe;
+ eqe = get_eqe(eq, eq->cons_index);
+ return (MTHCA_EQ_ENTRY_OWNER_HW & eqe->owner) ? NULL : eqe;
}
-static inline void set_eqe_hw(struct mthca_eq *eq, int entry)
+static inline void set_eqe_hw(struct mthca_eqe *eqe)
{
- get_eqe(eq, entry)->owner = MTHCA_EQ_ENTRY_OWNER_HW;
+ eqe->owner = MTHCA_EQ_ENTRY_OWNER_HW;
}
static void port_change(struct mthca_dev *dev, int port, int active)
@@ -235,10 +236,10 @@ static void mthca_eq_int(struct mthca_de
{
struct mthca_eqe *eqe;
int disarm_cqn;
+ int eqes_found = 0;
- while (next_eqe_sw(eq)) {
+ while ((eqe = next_eqe_sw(eq))) {
int set_ci = 0;
- eqe = get_eqe(eq, eq->cons_index);
/*
* Make sure we read EQ entry contents after we've
@@ -328,12 +329,13 @@ static void mthca_eq_int(struct mthca_de
break;
};
- set_eqe_hw(eq, eq->cons_index);
- eq->cons_index = (eq->cons_index + 1) & (eq->nent - 1);
+ set_eqe_hw(eqe);
+ ++eq->cons_index;
+ eqes_found = 1;
if (set_ci) {
wmb(); /* see comment below */
- set_eq_ci(dev, eq->eqn, eq->cons_index);
+ set_eq_ci(dev, eq, eq->cons_index);
set_ci = 0;
}
}
@@ -347,8 +349,10 @@ static void mthca_eq_int(struct mthca_de
* possibility of the HCA writing an entry and then
* having set_eqe_hw() overwrite the owner field.
*/
- wmb();
- set_eq_ci(dev, eq->eqn, eq->cons_index);
+ if (likely(eqes_found)) {
+ wmb();
+ set_eq_ci(dev, eq, eq->cons_index);
+ }
eq_req_not(dev, eq->eqn);
}
@@ -362,7 +366,7 @@ static irqreturn_t mthca_interrupt(int i
if (dev->eq_table.clr_mask)
writel(dev->eq_table.clr_mask, dev->eq_table.clr_int);
- while ((ecr = readl(dev->hcr + MTHCA_ECR_OFFSET + 4)) != 0) {
+ if ((ecr = readl(dev->hcr + MTHCA_ECR_OFFSET + 4)) != 0) {
work = 1;
writel(ecr, dev->hcr + MTHCA_ECR_CLR_OFFSET + 4);
@@ -440,7 +444,7 @@ static int __devinit mthca_create_eq(str
}
for (i = 0; i < nent; ++i)
- set_eqe_hw(eq, i);
+ set_eqe_hw(get_eqe(eq, i));
eq->eqn = mthca_alloc(&dev->eq_table.alloc);
if (eq->eqn == -1)
diff -puN drivers/infiniband/hw/mthca/mthca_provider.h~infiniband-mthca-optimize-event-queue-handling drivers/infiniband/hw/mthca/mthca_provider.h
--- 25/drivers/infiniband/hw/mthca/mthca_provider.h~infiniband-mthca-optimize-event-queue-handling 2005-01-23 22:25:01.249412232 -0800
+++ 25-akpm/drivers/infiniband/hw/mthca/mthca_provider.h 2005-01-23 22:25:01.253411624 -0800
@@ -66,11 +66,11 @@ struct mthca_eq {
struct mthca_dev *dev;
int eqn;
u32 ecr_mask;
+ u32 cons_index;
u16 msi_x_vector;
u16 msi_x_entry;
int have_irq;
int nent;
- int cons_index;
struct mthca_buf_list *page_list;
struct mthca_mr mr;
};
_