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# http://mvapich.cse.ohio-state.edu/benchmarks/
from mpi4py import MPI
def osu_bw(
BENCHMARH="MPI Bandwidth Test",
skip=10,
loop=100,
window_size=64,
skip_large=2,
loop_large=20,
window_size_large=64,
large_message_size=8192,
MAX_MSG_SIZE=1 << 22,
):
comm = MPI.COMM_WORLD
myid = comm.Get_rank()
numprocs = comm.Get_size()
if numprocs != 2:
if myid == 0:
errmsg = "This test requires exactly two processes"
else:
errmsg = None
raise SystemExit(errmsg)
s_buf = allocate(MAX_MSG_SIZE)
r_buf = allocate(MAX_MSG_SIZE)
if myid == 0:
print(f"# {BENCHMARH}")
if myid == 0:
print(f"# {'Size [B]':<8s}{'Latency [us]':>20s}")
message_sizes = [2**i for i in range(30)]
for size in message_sizes:
if size > MAX_MSG_SIZE:
break
if size > large_message_size:
skip = skip_large
loop = loop_large
window_size = window_size_large
iterations = list(range(loop + skip))
window_sizes = list(range(window_size))
requests = [MPI.REQUEST_NULL] * window_size
#
comm.Barrier()
if myid == 0:
s_msg = [s_buf, size, MPI.BYTE]
r_msg = [r_buf, 4, MPI.BYTE]
for i in iterations:
if i == skip:
t_start = MPI.Wtime()
for j in window_sizes:
requests[j] = comm.Isend(s_msg, 1, 100)
MPI.Request.Waitall(requests)
comm.Recv(r_msg, 1, 101)
t_end = MPI.Wtime()
elif myid == 1:
s_msg = [s_buf, 4, MPI.BYTE]
r_msg = [r_buf, size, MPI.BYTE]
for i in iterations:
if i == skip:
pass
for j in window_sizes:
requests[j] = comm.Irecv(r_msg, 0, 100)
MPI.Request.Waitall(requests)
comm.Send(s_msg, 0, 101)
#
if myid == 0:
MB = size / 1e6 * loop * window_size
s = t_end - t_start
bandwidth = MB / s
print(f"{size:-10d}{bandwidth:20.2f}")
def allocate(n):
try:
import mmap
return mmap.mmap(-1, n)
except (ImportError, OSError):
try:
from numpy import zeros
return zeros(n, "B")
except ImportError:
from array import array
return array("B", [0]) * n
if __name__ == "__main__":
osu_bw()
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