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base repository: GlasgowEmbedded/glasgow
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head repository: GlasgowEmbedded/glasgow
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compare: 21641a13c6a0
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  • 1 commit
  • 1 file changed
  • 1 contributor

Commits on Aug 31, 2019

  1. applet.internal.benchmark: add latency benchmark

    @electroniceel @whitequark
    electroniceel authored and whitequark committed Aug 31, 2019

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    21641a1 View commit details
Showing with 38 additions and 2 deletions.
  1. +38 −2 software/glasgow/applet/internal/benchmark/__init__.py
40 changes: 38 additions & 2 deletions software/glasgow/applet/internal/benchmark/__init__.py
View file
Original file line number Diff line number Diff line change
@@ -3,6 +3,7 @@
import struct
import array
import time
import statistics
from nmigen.compat import *

from ....gateware.lfsr import *
@@ -97,9 +98,13 @@ class BenchmarkApplet(GlasgowApplet, name="benchmark"):
* loopback: host emits an endless stream of data via one FIFOs, device mirrors it all back,
host validates
(simulates an SPI protocol subtarget)
* latency: host sends one packet, device sends it back, time until the packet is received back
on the host is measured
(simulates cases where a transaction with the DUT relies on feedback from the host;
also useful for comparing different usb stacks or usb data paths like hubs or network bridges)
"""

__all_modes = ["source", "sink", "loopback"]
__all_modes = ["source", "sink", "loopback", "latency"]

def build(self, target, args):
self.mux_interface = iface = \
@@ -192,13 +197,44 @@ async def counter():
error = (actual != golden)
count = None

if mode == "latency":
packetmax = golden[:512]
count = 0
error = False
roundtriptime = []

await device.write_register(self.__addr_mode, MODE_LOOPBACK)
await iface.reset()
counter_fut = asyncio.ensure_future(counter())

while count < args.count:
begin = time.perf_counter()
await iface.write(packetmax)
actual = await iface.read(len(packetmax))
end = time.perf_counter()

# calculate roundtrip time in µs
roundtriptime.append((end - begin) * 1000000)
if actual != packetmax:
error = True
break
count += len(packetmax) * 2

counter_fut.cancel()

if error:
if count is None:
self.logger.error("mode %s failed!", mode)
else:
self.logger.error("mode %s failed at %#x!", mode, count)
else:
self.logger.info("mode %s: %.2f MiB/s (%.2f Mb/s)",
if mode == "latency":
self.logger.info("mode %s: %.2f µs stddev: %.2f µs",
mode,
statistics.mean(roundtriptime),
statistics.pstdev(roundtriptime))
else:
self.logger.info("mode %s: %.2f MiB/s (%.2f Mb/s)",
mode,
(length / (end - begin)) / (1 << 20),
(length / (end - begin)) / (1 << 17))