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authorPeter Xu <peterx@redhat.com>2018-04-27 17:07:24 +0800
committerMichael S. Tsirkin <mst@redhat.com>2018-05-23 03:14:41 +0300
commitffcbbe722fcb3c162318cba1b94a115498e25acd (patch)
tree39d0dd6539a56592896ceebd38741e26c9721dfc /hw
parentb7b126442977dcfa5641e38b084bd13a0b366cff (diff)
vhost: add trace for IOTLB miss
Add some trace points for IOTLB translation for vhost. After vhost-user is setup, the only IO path that QEMU will participate should be the IOMMU translation, so it'll be good we can track this with explicit timestamps when needed to see how long time we take to do the translation, and whether there's anything stuck inside. It might be useful for triaging vhost-user problems. Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/virtio/trace-events1
-rw-r--r--hw/virtio/vhost.c7
2 files changed, 8 insertions, 0 deletions
diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index 1422ff03ab..07bcbe9e85 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -6,6 +6,7 @@ vhost_region_add_section(const char *name, uint64_t gpa, uint64_t size, uint64_t
vhost_region_add_section_merge(const char *name, uint64_t new_size, uint64_t gpa, uint64_t owr) "%s: size: 0x%"PRIx64 " gpa: 0x%"PRIx64 " owr: 0x%"PRIx64
vhost_region_add_section_aligned(const char *name, uint64_t gpa, uint64_t size, uint64_t host) "%s: 0x%"PRIx64"+0x%"PRIx64" @ 0x%"PRIx64
vhost_section(const char *name, int r) "%s:%d"
+vhost_iotlb_miss(void *dev, int step) "%p step %d"
# hw/virtio/vhost-user.c
vhost_user_postcopy_end_entry(void) ""
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 9d5850a7d7..b08290036d 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -894,12 +894,15 @@ int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write)
rcu_read_lock();
+ trace_vhost_iotlb_miss(dev, 1);
+
iotlb = address_space_get_iotlb_entry(dev->vdev->dma_as,
iova, write);
if (iotlb.target_as != NULL) {
ret = vhost_memory_region_lookup(dev, iotlb.translated_addr,
&uaddr, &len);
if (ret) {
+ trace_vhost_iotlb_miss(dev, 3);
error_report("Fail to lookup the translated address "
"%"PRIx64, iotlb.translated_addr);
goto out;
@@ -911,10 +914,14 @@ int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write)
ret = vhost_backend_update_device_iotlb(dev, iova, uaddr,
len, iotlb.perm);
if (ret) {
+ trace_vhost_iotlb_miss(dev, 4);
error_report("Fail to update device iotlb");
goto out;
}
}
+
+ trace_vhost_iotlb_miss(dev, 2);
+
out:
rcu_read_unlock();