Somewhat reduce overhead on receive interrupts, and count the number
of interrupts where that works (fastrcvint).
Signed-off-by: Bryan O'Sullivan <[email protected]>
diff -r cc6d7f2537b2 -r ab2b013f1f95 drivers/infiniband/hw/ipath/ipath_common.h
--- a/drivers/infiniband/hw/ipath/ipath_common.h Fri May 12 15:55:28 2006 -0700
+++ b/drivers/infiniband/hw/ipath/ipath_common.h Fri May 12 15:55:28 2006 -0700
@@ -96,8 +96,8 @@ struct infinipath_stats {
__u64 sps_hwerrs;
/* number of times IB link changed state unexpectedly */
__u64 sps_iblink;
- /* no longer used; left for compatibility */
- __u64 sps_unused3;
+ /* kernel receive interrupts that didn't read intstat */
+ __u64 sps_fastrcvint;
/* number of kernel (port0) packets received */
__u64 sps_port0pkts;
/* number of "ethernet" packets sent by driver */
diff -r cc6d7f2537b2 -r ab2b013f1f95 drivers/infiniband/hw/ipath/ipath_driver.c
--- a/drivers/infiniband/hw/ipath/ipath_driver.c Fri May 12 15:55:28 2006 -0700
+++ b/drivers/infiniband/hw/ipath/ipath_driver.c Fri May 12 15:55:28 2006 -0700
@@ -936,12 +936,7 @@ void ipath_kreceive(struct ipath_devdata
(u32)le64_to_cpu(*dd->ipath_hdrqtailptr))
goto done;
-gotmore:
- /*
- * read only once at start. If in flood situation, this helps
- * performance slightly. If more arrive while we are processing,
- * we'll come back here and do them
- */
+ /* read only once at start for performance */
hdrqtail = (u32)le64_to_cpu(*dd->ipath_hdrqtailptr);
for (i = 0, l = dd->ipath_port0head; l != hdrqtail; i++) {
@@ -1070,10 +1065,6 @@ gotmore:
dd->ipath_port0head = l;
- if (hdrqtail != (u32)le64_to_cpu(*dd->ipath_hdrqtailptr))
- /* more arrived while we handled first batch */
- goto gotmore;
-
if (pkttot > ipath_stats.sps_maxpkts_call)
ipath_stats.sps_maxpkts_call = pkttot;
ipath_stats.sps_port0pkts += pkttot;
diff -r cc6d7f2537b2 -r ab2b013f1f95 drivers/infiniband/hw/ipath/ipath_intr.c
--- a/drivers/infiniband/hw/ipath/ipath_intr.c Fri May 12 15:55:28 2006 -0700
+++ b/drivers/infiniband/hw/ipath/ipath_intr.c Fri May 12 15:55:28 2006 -0700
@@ -493,10 +493,10 @@ static void handle_errors(struct ipath_d
continue;
if (hd == (tl + 1) ||
(!hd && tl == dd->ipath_hdrqlast)) {
+ if (i == 0)
+ chkerrpkts = 1;
dd->ipath_lastrcvhdrqtails[i] = tl;
pd->port_hdrqfull++;
- if (i == 0)
- chkerrpkts = 1;
}
}
}
@@ -678,7 +678,12 @@ set:
dd->ipath_sendctrl);
}
-static void handle_rcv(struct ipath_devdata *dd, u32 istat)
+/*
+ * Handle receive interrupts for user ports; this means a user
+ * process was waiting for a packet to arrive, and didn't want
+ * to poll
+ */
+static void handle_urcv(struct ipath_devdata *dd, u32 istat)
{
u64 portr;
int i;
@@ -688,22 +693,17 @@ static void handle_rcv(struct ipath_devd
infinipath_i_rcvavail_mask)
| ((istat >> INFINIPATH_I_RCVURG_SHIFT) &
infinipath_i_rcvurg_mask);
- for (i = 0; i < dd->ipath_cfgports; i++) {
+ for (i = 1; i < dd->ipath_cfgports; i++) {
struct ipath_portdata *pd = dd->ipath_pd[i];
- if (portr & (1 << i) && pd &&
- pd->port_cnt) {
- if (i == 0)
- ipath_kreceive(dd);
- else if (test_bit(IPATH_PORT_WAITING_RCV,
- &pd->port_flag)) {
- int rcbit;
- clear_bit(IPATH_PORT_WAITING_RCV,
- &pd->port_flag);
- rcbit = i + INFINIPATH_R_INTRAVAIL_SHIFT;
- clear_bit(1UL << rcbit, &dd->ipath_rcvctrl);
- wake_up_interruptible(&pd->port_wait);
- rcvdint = 1;
- }
+ if (portr & (1 << i) && pd && pd->port_cnt &&
+ test_bit(IPATH_PORT_WAITING_RCV, &pd->port_flag)) {
+ int rcbit;
+ clear_bit(IPATH_PORT_WAITING_RCV,
+ &pd->port_flag);
+ rcbit = i + INFINIPATH_R_INTRAVAIL_SHIFT;
+ clear_bit(1UL << rcbit, &dd->ipath_rcvctrl);
+ wake_up_interruptible(&pd->port_wait);
+ rcvdint = 1;
}
}
if (rcvdint) {
@@ -721,19 +721,66 @@ irqreturn_t ipath_intr(int irq, void *da
struct ipath_devdata *dd = data;
u32 istat;
ipath_err_t estat = 0;
+ irqreturn_t ret;
+ u32 p0bits;
static unsigned unexpected = 0;
- irqreturn_t ret;
+ static const u32 port0rbits = (1U<<INFINIPATH_I_RCVAVAIL_SHIFT) |
+ (1U<<INFINIPATH_I_RCVURG_SHIFT);
+
+ ipath_stats.sps_ints++;
if(!(dd->ipath_flags & IPATH_PRESENT)) {
- /* this is mostly so we don't try to touch the chip while
- * it is being reset */
- /*
- * This return value is perhaps odd, but we do not want the
+ /*
+ * This return value is not great, but we do not want the
* interrupt core code to remove our interrupt handler
* because we don't appear to be handling an interrupt
* during a chip reset.
*/
return IRQ_HANDLED;
+ }
+
+ /*
+ * this needs to be flags&initted, not statusp, so we keep
+ * taking interrupts even after link goes down, etc.
+ * Also, we *must* clear the interrupt at some point, or we won't
+ * take it again, which can be real bad for errors, etc...
+ */
+
+ if (!(dd->ipath_flags & IPATH_INITTED)) {
+ ipath_bad_intr(dd, &unexpected);
+ ret = IRQ_NONE;
+ goto bail;
+ }
+
+ /*
+ * We try to avoid readint the interrupt status register, since
+ * that's a PIO read, and stalls the processor for up to about
+ * ~0.25 usec. The idea is that if we processed a port0 packet,
+ * we blindly clear the port 0 receive interrupt bits, and nothing
+ * else, then return. If other interrupts are pending, the chip
+ * will re-interrupt us as soon as we write the intclear register.
+ * We then won't process any more kernel packets (if not the 2nd
+ * time, then the 3rd or 4th) and we'll then handle the other
+ * interrupts. We clear the interrupts first so that we don't
+ * lose intr for later packets that arrive while we are processing.
+ */
+ if (dd->ipath_port0head !=
+ (u32)le64_to_cpu(*dd->ipath_hdrqtailptr)) {
+ u32 oldhead = dd->ipath_port0head;
+ if(dd->ipath_flags & IPATH_GPIO_INTR) {
+ ipath_write_kreg(dd, dd->ipath_kregs->kr_gpio_clear,
+ (u64) (1 << 2));
+ p0bits = port0rbits | INFINIPATH_I_GPIO;
+ }
+ else
+ p0bits = port0rbits;
+ ipath_write_kreg(dd, dd->ipath_kregs->kr_intclear, p0bits);
+ ipath_kreceive(dd);
+ if(oldhead != dd->ipath_port0head) {
+ ipath_stats.sps_fastrcvint++;
+ goto done;
+ }
+ istat = ipath_read_kreg32(dd, dd->ipath_kregs->kr_intstatus);
}
istat = ipath_read_kreg32(dd, dd->ipath_kregs->kr_intstatus);
@@ -749,31 +796,17 @@ irqreturn_t ipath_intr(int irq, void *da
goto bail;
}
- ipath_stats.sps_ints++;
-
- /*
- * this needs to be flags&initted, not statusp, so we keep
- * taking interrupts even after link goes down, etc.
- * Also, we *must* clear the interrupt at some point, or we won't
- * take it again, which can be real bad for errors, etc...
- */
-
- if (!(dd->ipath_flags & IPATH_INITTED)) {
- ipath_bad_intr(dd, &unexpected);
- ret = IRQ_NONE;
- goto bail;
- }
if (unexpected)
unexpected = 0;
- ipath_cdbg(VERBOSE, "intr stat=0x%x\n", istat);
-
- if (istat & ~infinipath_i_bitsextant)
+ if(unlikely(istat & ~infinipath_i_bitsextant))
ipath_dev_err(dd,
"interrupt with unknown interrupts %x set\n",
istat & (u32) ~ infinipath_i_bitsextant);
-
- if (istat & INFINIPATH_I_ERROR) {
+ else
+ ipath_cdbg(VERBOSE, "intr stat=0x%x\n", istat);
+
+ if(unlikely(istat & INFINIPATH_I_ERROR)) {
ipath_stats.sps_errints++;
estat = ipath_read_kreg64(dd,
dd->ipath_kregs->kr_errorstatus);
@@ -791,7 +824,14 @@ irqreturn_t ipath_intr(int irq, void *da
handle_errors(dd, estat);
}
+ p0bits = port0rbits;
if (istat & INFINIPATH_I_GPIO) {
+ /*
+ * Packets are available in the port 0 rcv queue.
+ * Eventually this needs to be generalized to check
+ * IPATH_GPIO_INTR, and the specific GPIO bit, if
+ * GPIO interrupts are used for anything else.
+ */
if (unlikely(!(dd->ipath_flags & IPATH_GPIO_INTR))) {
u32 gpiostatus;
gpiostatus = ipath_read_kreg32(
@@ -805,14 +845,7 @@ irqreturn_t ipath_intr(int irq, void *da
/* Clear GPIO status bit 2 */
ipath_write_kreg(dd, dd->ipath_kregs->kr_gpio_clear,
(u64) (1 << 2));
-
- /*
- * Packets are available in the port 0 rcv queue.
- * Eventually this needs to be generalized to check
- * IPATH_GPIO_INTR, and the specific GPIO bit, if
- * GPIO interrupts are used for anything else.
- */
- ipath_kreceive(dd);
+ p0bits |= INFINIPATH_I_GPIO;
}
}
@@ -825,6 +858,25 @@ irqreturn_t ipath_intr(int irq, void *da
*/
ipath_write_kreg(dd, dd->ipath_kregs->kr_intclear, istat);
+ /*
+ * we check for both transition from empty to non-empty, and urgent
+ * packets (those with the interrupt bit set in the header), and
+ * if enabled, the GPIO bit 2 interrupt used for port0 on some
+ * HT-400 boards.
+ * Do this before checking for pio buffers available, since
+ * receives can overflow; piobuf waiters can afford a few
+ * extra cycles, since they were waiting anyway.
+ */
+ if(istat & p0bits) {
+ ipath_kreceive(dd);
+ istat &= ~port0rbits;
+ }
+ if (istat & ((infinipath_i_rcvavail_mask <<
+ INFINIPATH_I_RCVAVAIL_SHIFT)
+ | (infinipath_i_rcvurg_mask <<
+ INFINIPATH_I_RCVURG_SHIFT)))
+ handle_urcv(dd, istat);
+
if (istat & INFINIPATH_I_SPIOBUFAVAIL) {
clear_bit(IPATH_S_PIOINTBUFAVAIL, &dd->ipath_sendctrl);
ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
@@ -836,17 +888,7 @@ irqreturn_t ipath_intr(int irq, void *da
handle_layer_pioavail(dd);
}
- /*
- * we check for both transition from empty to non-empty, and urgent
- * packets (those with the interrupt bit set in the header)
- */
-
- if (istat & ((infinipath_i_rcvavail_mask <<
- INFINIPATH_I_RCVAVAIL_SHIFT)
- | (infinipath_i_rcvurg_mask <<
- INFINIPATH_I_RCVURG_SHIFT)))
- handle_rcv(dd, istat);
-
+done:
ret = IRQ_HANDLED;
bail:
diff -r cc6d7f2537b2 -r ab2b013f1f95 drivers/infiniband/hw/ipath/ipath_stats.c
--- a/drivers/infiniband/hw/ipath/ipath_stats.c Fri May 12 15:55:28 2006 -0700
+++ b/drivers/infiniband/hw/ipath/ipath_stats.c Fri May 12 15:55:28 2006 -0700
@@ -185,7 +185,6 @@ static void ipath_qcheck(struct ipath_de
dd->ipath_port0head,
(unsigned long long)
ipath_stats.sps_port0pkts);
- ipath_kreceive(dd);
}
dd->ipath_lastport0rcv_cnt = ipath_stats.sps_port0pkts;
}
-
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