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drtio: remove FIFO empty local detection optimization

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It optimizes a marginal case, it is difficult to get right
(need to know the size of the FIFO for each channel), and
it adds complexity and potential bug sources.
This commit is contained in:
Sebastien Bourdeauducq 2017-01-10 14:31:03 -06:00
parent f75fffcf96
commit e624f45369
2 changed files with 8 additions and 19 deletions
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12
artiq/gateware/drtio/rt_controller.py
View File

@ -139,8 +139,6 @@ class RTController(Module):
cond_sequence_error = self.cri.o_timestamp < last_timestamps.dat_r
cond_underflow = ((self.cri.o_timestamp[fine_ts_width:]
- self.csrs.underflow_margin.storage[fine_ts_width:]) < self.counter.value_sys)
cond_fifo_emptied = ((last_timestamps.dat_r[fine_ts_width:] < self.counter.value_sys)
& (last_timestamps.dat_r != 0))
fsm.act("IDLE",
If(self.cri.cmd == cri.commands["write"],
@ -161,13 +159,9 @@ class RTController(Module):
rt_packets.write_stb.eq(1),
If(rt_packets.write_ack,
fifo_spaces.we.eq(1),
If(cond_fifo_emptied,
fifo_spaces.dat_w.eq(1),
).Else(
fifo_spaces.dat_w.eq(fifo_spaces.dat_r - 1)
),
fifo_spaces.dat_w.eq(fifo_spaces.dat_r - 1),
last_timestamps.we.eq(1),
If(~cond_fifo_emptied & (fifo_spaces.dat_r <= 1),
If(fifo_spaces.dat_r <= 1,
NextState("GET_FIFO_SPACE")
).Else(
NextState("IDLE")
@ -189,7 +183,7 @@ class RTController(Module):
fifo_spaces.we.eq(1),
rt_packets.fifo_space_not_ack.eq(1),
If(rt_packets.fifo_space_not,
If(rt_packets.fifo_space > 0,
If(rt_packets.fifo_space != 0,
NextState("IDLE")
).Else(
NextState("GET_FIFO_SPACE")

15
artiq/test/gateware/drtio/test_full_stack.py
View File

@ -174,15 +174,6 @@ class TestFullStack(unittest.TestCase):
# check that some writes caused FIFO space requests
self.assertGreater(max_wlen, 5)
def test_fifo_emptied():
# wait for all TTL events to execute
while len(ttl_changes) < len(correct_ttl_changes):
yield
# check "last timestamp passed" FIFO empty condition
delay(1000*8)
wlen = yield from write(0, 1)
self.assertEqual(wlen, 2)
def test_tsc_error():
err_present = yield from mgr.packet_err_present.read()
self.assertEqual(err_present, 0)
@ -203,6 +194,10 @@ class TestFullStack(unittest.TestCase):
err_present = yield from mgr.packet_err_present.read()
self.assertEqual(err_present, 0)
def wait_ttl_events():
while len(ttl_changes) < len(correct_ttl_changes):
yield
def test():
while not (yield from dut.master.link_layer.link_status.read()):
yield
@ -213,8 +208,8 @@ class TestFullStack(unittest.TestCase):
yield from test_sequence_error()
yield from test_fifo_space()
yield from test_large_data()
yield from test_fifo_emptied()
yield from test_tsc_error()
yield from wait_ttl_events()
@passive
def check_ttls():