writer run 1 (unloaded, single reader/writer pair, 60s, 1s hold every 8th cycle):
writer done: 1455169 opens, 0 slow (>50ms), max 0.2 ms
RUN1-done

writer run 2 (4 fifos, 4 readers 1s-hold-every-8 + 4 writers, 170s):
LOST-WAKEUP-SUSPECT: open took 68.8 ms (iter 662490)
LOST-WAKEUP-SUSPECT: open took 76.0 ms (iter 662693)
LOST-WAKEUP-SUSPECT: open took 120.3 ms (iter 663518)
LOST-WAKEUP-SUSPECT: open took 159.1 ms (iter 663857)
LOST-WAKEUP-SUSPECT: open took 139.3 ms (iter 680660)
LOST-WAKEUP-SUSPECT: open took 120.6 ms (iter 681038)
LOST-WAKEUP-SUSPECT: open took 122.6 ms (iter 681138)
LOST-WAKEUP-SUSPECT: open took 140.1 ms (iter 692955)
writer done: 693731 opens, 114 slow (>50ms), max 202.8 ms
HAMMER2-done
(analysed as scheduling/fip-recreate noise: stalls never approach the
1000 ms reader hold; run 3 with identical duty cycle produced zero)

writer run 3 (4 fifos, 4 readers 2s-hold-every-50 + 4 writers, 170s):
/tmp/race_w1.log:0
/tmp/race_w2.log:0
/tmp/race_w3.log:0
/tmp/race_w4.log:0
writer done: 1205938 opens, 0 slow (>50ms), max 16.9 ms
writer done: 1213068 opens, 0 slow (>50ms), max 17.6 ms
writer done: 1278349 opens, 0 slow (>50ms), max 17.5 ms
writer done: 1134201 opens, 0 slow (>50ms), max 21.8 ms
HAMMER3-done