Specifying --tilethreads=2 for 1-tile content is ~43% slower.

Not sure if this is a bug or falls under user error, but filing either way:

$ time ./build/tools/dav1d -i oliver_480p.ivf -o out.yuv
dav1d 859ae6a - by VideoLAN
Decoded 7212/7212 frames (100.0%)

real	0m21.354s
user	0m16.675s
sys	0m4.675s

$ time ./build/tools/dav1d --tilethreads=2 -i oliver_480p.ivf -o out.yuv
dav1d 859ae6a - by VideoLAN
Decoded 7212/7212 frames (100.0%)

real	0m37.754s
user	0m33.918s
sys	0m8.558s

Can't share the content, but you might check here https://www.youtube.com/watch?v=2nXYbGmF3_Q