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authorUjjal Singh <ujjal.singh@intel.com>2017-08-22 20:31:18 -0400
committerVinod Koul <vinod.koul@intel.com>2017-08-23 21:32:21 +0530
commit268e2519f5b7101d707a0df32e628e9990bc0da6 (patch)
treee7bd1da9ec7fe99d166646c4121504997f4a7cd2 /drivers/dma/ioat/sysfs.c
parent2e442003ab2fbc386bc04b243f6aaaebdbfbb821 (diff)
dmaengine: ioatdma: Add intr_coalesce sysfs entry
We observed performance increase with DMA copy from memory to MMIO by changing the interrupt coalescing value to 0. The previous set value was projected on the C5xxx Xeon platform and no longer holds true. Removing hard coded value and providing a tune-able in sysfs in order to allow user to tune this on a per channel basis. By default this value will be set to 0. Example of sysfs variable importing for interrupt coalescing value from command line: echo 5> /sys/devices/pci0000:00/0000:00:04.0/dma/dma0chan0/ quickdata/intr_coalesce Reported-by: Nithin Sujir <nsujir@tintri.com> Signed-off-by: Ujjal Singh <ujjal.singh@intel.com> Acked-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers/dma/ioat/sysfs.c')
-rw-r--r--drivers/dma/ioat/sysfs.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/drivers/dma/ioat/sysfs.c b/drivers/dma/ioat/sysfs.c
index cb4a857ee21b..3ac677f29e8f 100644
--- a/drivers/dma/ioat/sysfs.c
+++ b/drivers/dma/ioat/sysfs.c
@@ -64,8 +64,24 @@ ioat_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
return entry->show(&ioat_chan->dma_chan, page);
}
+static ssize_t
+ioat_attr_store(struct kobject *kobj, struct attribute *attr,
+const char *page, size_t count)
+{
+ struct ioat_sysfs_entry *entry;
+ struct ioatdma_chan *ioat_chan;
+
+ entry = container_of(attr, struct ioat_sysfs_entry, attr);
+ ioat_chan = container_of(kobj, struct ioatdma_chan, kobj);
+
+ if (!entry->store)
+ return -EIO;
+ return entry->store(&ioat_chan->dma_chan, page, count);
+}
+
const struct sysfs_ops ioat_sysfs_ops = {
.show = ioat_attr_show,
+ .store = ioat_attr_store,
};
void ioat_kobject_add(struct ioatdma_device *ioat_dma, struct kobj_type *type)
@@ -121,11 +137,37 @@ static ssize_t ring_active_show(struct dma_chan *c, char *page)
}
static struct ioat_sysfs_entry ring_active_attr = __ATTR_RO(ring_active);
+static ssize_t intr_coalesce_show(struct dma_chan *c, char *page)
+{
+ struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+
+ return sprintf(page, "%d\n", ioat_chan->intr_coalesce);
+}
+
+static ssize_t intr_coalesce_store(struct dma_chan *c, const char *page,
+size_t count)
+{
+ int intr_coalesce = 0;
+ struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+
+ if (sscanf(page, "%du", &intr_coalesce) != -1) {
+ if ((intr_coalesce < 0) ||
+ (intr_coalesce > IOAT_INTRDELAY_MASK))
+ return -EINVAL;
+ ioat_chan->intr_coalesce = intr_coalesce;
+ }
+
+ return count;
+}
+
+static struct ioat_sysfs_entry intr_coalesce_attr = __ATTR_RW(intr_coalesce);
+
static struct attribute *ioat_attrs[] = {
&ring_size_attr.attr,
&ring_active_attr.attr,
&ioat_cap_attr.attr,
&ioat_version_attr.attr,
+ &intr_coalesce_attr.attr,
NULL,
};