[  154.074065] [drm:drm_ioctl] pid=2323, dev=0xe200, auth=1, I915_GEM_WAIT
[  154.074748] i915_gem_wait_ioctl: timeout 0.500000000 -> 0.499993351
[  154.075390] [drm:drm_ioctl] ret = -512
...
[  155.072528] [drm:drm_ioctl] pid=2323, dev=0xe200, auth=1, I915_GEM_WAIT
[  155.073234] i915_gem_wait_ioctl: timeout 0.488539596 -> 0.488535373
[  155.073916] [drm:drm_ioctl] ret = -512
[  155.074605] [drm:drm_ioctl] pid=2323, dev=0xe200, auth=1, I915_GEM_WAIT
[  155.075307] i915_gem_wait_ioctl: timeout 0.488535373 -> 0.488532529

Walltime of 1s, but actual wait time of ~12ms.

Each ioctl is taking ~1.4ms (inside drmIoctl) with a further interval of ~0.7ms
between ioctls. And we account for 3us.