kernel/wr_pstats: dump whole cntrs overflow information in irq handler

On higher storm of traffic, in the time between scheduling the tasklet and executing it, I was loosing cntrs overflow information already (was overwritten by all-the-time-incrementing counters in HDL).

kernel/wr_pstats: dump whole cntrs overflow information in irq handler
On higher storm of traffic, in the time between scheduling the tasklet and executing it, I was loosing cntrs overflow information already (was overwritten by all-the-time-incrementing counters in HDL).
4c9d7912 · Grzegorz Daniluk · Alessandro Rubini · 8ff7b4d6 · 4c9d7912
Commit 4c9d7912 authored Jun 25, 2014 by Grzegorz Daniluk Committed by Alessandro Rubini Jul 10, 2014
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wr_pstats.c kernel/wr_pstats/wr_pstats.c +44 -28

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--- a/kernel/wr_pstats/wr_pstats.c
+++ b/kernel/wr_pstats/wr_pstats.c
@@ -53,6 +53,7 @@ struct cntrs_dev {
 	/* circular bufer for passing Port's IRQ mask between irq handler and
 	 * the tasklet */
 	uint32_t port_irqs[PSTATS_IRQBUFSZ];
+  uint64_t overflows[PSTATS_IRQBUFSZ][PSTATS_NPORTS];
 	volatile int irqs_head;
 	int irqs_tail;
 };
@@ -118,7 +119,7 @@ static uint64_t pstats_irq_cntrs(int port)
 static void pstats_tlet_fn(unsigned long arg)
 {
 	uint32_t irqs;
-	uint64_t cntrs_ov;
+	uint64_t *cntrs_ov;
 	int port, cntr;
 	unsigned int *ptr;
 	struct cntrs_dev *device = (struct cntrs_dev *)arg;
@@ -130,44 +131,59 @@ static void pstats_tlet_fn(unsigned long arg)
 		device->irqs_tail += PSTATS_IRQBUFSZ;
 	}

-	irqs = device->port_irqs[device->irqs_tail++ % PSTATS_IRQBUFSZ];
-
-	/* level 1 of IRQs is device->port_irqs where each bit set to 1 says
-	 * there is at least one overflowed counter on the port correcponding
-	 * to the bit */
-	for (port = 0; port < pstats_nports; ++port) {
-		if (!(irqs>>port & 0x01))
-			continue;	/*there is no irq from this port*/
-
-		/* Level 2 of IRQs is reading additional IRQ flags register for
-		 * each port that has bit in device->port_irqs set to 1. This
-		 * register is a set of IRQ flags per-counter for a given port.
-		 * That means, when i-th bit in cntrs_ov is set, i-th counter
-		 * for this port has to be incremented by 1<<PSTATS_MSB_SHIFT */
-		spin_lock(&device->port_mutex[port]);
-		cntrs_ov = pstats_irq_cntrs(port);
-		for (cntr = 0; cntr < PSTATS_CNT_PP; ++cntr) {
-			/*decode counters overflow flags to increment coutners*/
-			if (cntrs_ov>>cntr & 0x01) {
-				ptr = cntr_idx(device->cntrs, port, cntr);
-				*ptr += 1<<PSTATS_MSB_SHIFT;
-			}
-		}
-		spin_unlock(&device->port_mutex[port]);
-	}
+  while(device->irqs_tail != device->irqs_head) {
+    //printk(KERN_WARNING "tlet head=%d, tail=%d\n", device->irqs_head, device->irqs_tail);
+	  irqs = device->port_irqs[device->irqs_tail];
+
+	  /* level 1 of IRQs is device->port_irqs where each bit set to 1 says
+	   * there is at least one overflowed counter on the port correcponding
+	   * to the bit */
+    //printk("irqs %5x\n", irqs);
+	  for (port = 0; port < pstats_nports; ++port) {
+	  	if (!(irqs>>port & 0x01))
+	  		continue;	/*there is no irq from this port*/
+
+	  	/* Level 2 of IRQs is reading additional IRQ flags register for
+	  	 * each port that has bit in device->port_irqs set to 1. This
+	  	 * register is a set of IRQ flags per-counter for a given port.
+	  	 * That means, when i-th bit in cntrs_ov is set, i-th counter
+	  	 * for this port has to be incremented by 1<<PSTATS_MSB_SHIFT */
+	  	spin_lock(&device->port_mutex[port]);
+	  	cntrs_ov = &(device->overflows[device->irqs_tail][port]);
+	  	//if(port==0)
+	  	//	printk(KERN_WARNING "cntrs_ov: %08x %08x\n", (uint32_t)((*cntrs_ov)>>32 & 0xffffffff),
+      //      (uint32_t)((*cntrs_ov) & 0x00ffffffffLL));
+	  	for (cntr = 0; cntr < PSTATS_CNT_PP; ++cntr) {
+	  		/*decode counters overflow flags to increment coutners*/
+	  		if ((*cntrs_ov)>>cntr & 0x01) {
+	  			ptr = cntr_idx(device->cntrs, port, cntr);
+	  			*ptr += 1<<PSTATS_MSB_SHIFT;
+	  		}
+	  	}
+	  	spin_unlock(&device->port_mutex[port]);
+	  }
+	  device->irqs_tail = (device->irqs_tail+1) % PSTATS_IRQBUFSZ;
+  }
 }
 DECLARE_TASKLET(proc_ports, pstats_tlet_fn, (unsigned long)&pstats_dev);

 static irqreturn_t pstats_irq_handler(int irq, void *devid)
 {
 	struct cntrs_dev *device = (struct cntrs_dev *)devid;
-	uint32_t irqs;
+	uint32_t irqs, i;

 	irqs = pstats_irq_status();

 	pstats_irq_disable(PSTATS_ALL_MSK);
 	pstats_irq_clear(irqs);
-	device->port_irqs[device->irqs_head++ % PSTATS_IRQBUFSZ] = irqs;
+	device->port_irqs[device->irqs_head] = irqs;
+  /* dump all overflow information so that we don't lose any if tasklet is
+   * delayed */
+  for(i=0; i<pstats_nports; ++i)
+    device->overflows[device->irqs_head][i] = pstats_irq_cntrs(i);
+
+	device->irqs_head = (device->irqs_head + 1) % PSTATS_IRQBUFSZ;
+	//device->port_irqs[device->irqs_head++ % PSTATS_IRQBUFSZ] = irqs;
 	tasklet_schedule(&proc_ports);
 	pstats_irq_enable(portmsk);