Added sync, some comments, and done some tinkering

This commit is contained in:
Martin Lilleeng Sætra 2021-05-18 21:19:07 +00:00
parent b6424b84fb
commit ad2be4b5a5
3 changed files with 30 additions and 278 deletions

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@ -1,252 +0,0 @@
# -*- coding: utf-8 -*-
"""
This python module implements SHMEM simulator class
Copyright (C) 2020 Norwegian Meteorological Institute
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
import logging
from GPUSimulators import Simulator
import numpy as np
class SHMEMSimulator(Simulator.BaseSimulator):
"""
Class which handles communication between simulators on different GPUs
NOTE: This class is only intended to be used by SHMEMSimulatorGroup
"""
def __init__(self, index, sim, grid):
self.logger = logging.getLogger(__name__)
autotuner = sim.context.autotuner
sim.context.autotuner = None;
boundary_conditions = sim.getBoundaryConditions()
super().__init__(sim.context,
sim.nx, sim.ny,
sim.dx, sim.dy,
boundary_conditions,
sim.cfl_scale,
sim.num_substeps,
sim.block_size[0], sim.block_size[1])
sim.context.autotuner = autotuner
self.index = index
self.sim = sim
self.grid = grid
#Get neighbor subdomain ids
self.east = grid.getEast(self.index)
self.west = grid.getWest(self.index)
self.north = grid.getNorth(self.index)
self.south = grid.getSouth(self.index)
#Get coordinate of this subdomain
#and handle global boundary conditions
new_boundary_conditions = Simulator.BoundaryCondition({
'north': Simulator.BoundaryCondition.Type.Dirichlet,
'south': Simulator.BoundaryCondition.Type.Dirichlet,
'east': Simulator.BoundaryCondition.Type.Dirichlet,
'west': Simulator.BoundaryCondition.Type.Dirichlet
})
gi, gj = grid.getCoordinate(self.index)
if (gi == 0 and boundary_conditions.west != Simulator.BoundaryCondition.Type.Periodic):
self.west = None
new_boundary_conditions.west = boundary_conditions.west;
if (gj == 0 and boundary_conditions.south != Simulator.BoundaryCondition.Type.Periodic):
self.south = None
new_boundary_conditions.south = boundary_conditions.south;
if (gi == grid.grid[0]-1 and boundary_conditions.east != Simulator.BoundaryCondition.Type.Periodic):
self.east = None
new_boundary_conditions.east = boundary_conditions.east;
if (gj == grid.grid[1]-1 and boundary_conditions.north != Simulator.BoundaryCondition.Type.Periodic):
self.north = None
new_boundary_conditions.north = boundary_conditions.north;
sim.setBoundaryConditions(new_boundary_conditions)
#Get number of variables
self.nvars = len(self.getOutput().gpu_variables)
#Shorthands for computing extents and sizes
gc_x = int(self.sim.getOutput()[0].x_halo)
gc_y = int(self.sim.getOutput()[0].y_halo)
nx = int(self.sim.nx)
ny = int(self.sim.ny)
#Set regions for ghost cells to read from
#These have the format [x0, y0, width, height]
self.read_e = np.array([ nx, 0, gc_x, ny + 2*gc_y])
self.read_w = np.array([gc_x, 0, gc_x, ny + 2*gc_y])
self.read_n = np.array([gc_x, ny, nx, gc_y])
self.read_s = np.array([gc_x, gc_y, nx, gc_y])
#Set regions for ghost cells to write to
self.write_e = self.read_e + np.array([gc_x, 0, 0, 0])
self.write_w = self.read_w - np.array([gc_x, 0, 0, 0])
self.write_n = self.read_n + np.array([0, gc_y, 0, 0])
self.write_s = self.read_s - np.array([0, gc_y, 0, 0])
#Allocate data for receiving
#Note that east and west also transfer ghost cells
#whilst north/south only transfer internal cells
#Reuses the width/height defined in the read-extets above
self.in_e = np.empty((self.nvars, self.read_e[3], self.read_e[2]), dtype=np.float32)
self.in_w = np.empty((self.nvars, self.read_w[3], self.read_w[2]), dtype=np.float32)
self.in_n = np.empty((self.nvars, self.read_n[3], self.read_n[2]), dtype=np.float32)
self.in_s = np.empty((self.nvars, self.read_s[3], self.read_s[2]), dtype=np.float32)
#Allocate data for sending
self.out_e = np.empty_like(self.in_e)
self.out_w = np.empty_like(self.in_w)
self.out_n = np.empty_like(self.in_n)
self.out_s = np.empty_like(self.in_s)
self.logger.debug("Simlator subdomain {:d} initialized on context {:s}".format(self.index, sim.context))
def substep(self, dt, step_number):
self.exchange()
self.sim.substep(dt, step_number)
def getOutput(self):
return self.sim.getOutput()
def synchronize(self):
self.sim.synchronize()
def check(self):
return self.sim.check()
def computeDt(self):
local_dt = np.array([np.float32(self.sim.computeDt())])
global_dt = np.empty(1, dtype=np.float32)
self.grid.comm.Allreduce(local_dt, global_dt, op=MPI.MIN)
self.logger.debug("Local dt: {:f}, global dt: {:f}".format(local_dt[0], global_dt[0]))
return global_dt[0]
def getExtent(self):
"""
Function which returns the extent of the subdomain with index
index in the grid
"""
width = self.sim.nx*self.sim.dx
height = self.sim.ny*self.sim.dy
i, j = self.grid.getCoordinate(self.index)
x0 = i * width
y0 = j * height
x1 = x0 + width
y1 = y0 + height
return [x0, x1, y0, y1]
def exchange(self):
ns_download_before_exchange()
# GLOBAL SYNC
ns_do_exchange()
# GLOBAL SYNC
ns_upload_after_exchange()
ew_download_before_exchange()
# GLOBAL SYNC
ew_do_exchange()
# GLOBAL SYNC
ew_upload_after_exchange()
def ns_download_before_exchange(self):
####
# First transfer internal cells north-south
####
#Download from the GPU
if self.north is not None:
for k in range(self.nvars):
self.sim.u0[k].download(self.sim.stream, cpu_data=self.out_n[k,:,:], asynch=True, extent=self.read_n)
if self.south is not None:
for k in range(self.nvars):
self.sim.u0[k].download(self.sim.stream, cpu_data=self.out_s[k,:,:], asynch=True, extent=self.read_s)
self.sim.stream.synchronize()
def ns_do_exchange(self):
#Send/receive to north/south neighbours
comm_send = []
comm_recv = []
if self.north is not None:
comm_send += [self.grid.comm.Isend(self.out_n, dest=self.north, tag=4*self.nt + 0)]
comm_recv += [self.grid.comm.Irecv(self.in_n, source=self.north, tag=4*self.nt + 1)]
if self.south is not None:
comm_send += [self.grid.comm.Isend(self.out_s, dest=self.south, tag=4*self.nt + 1)]
comm_recv += [self.grid.comm.Irecv(self.in_s, source=self.south, tag=4*self.nt + 0)]
#Wait for incoming transfers to complete
for comm in comm_recv:
comm.wait()
def ns_upload_after_exchange(self):
#Upload to the GPU
if self.north is not None:
for k in range(self.nvars):
self.sim.u0[k].upload(self.sim.stream, self.in_n[k,:,:], extent=self.write_n)
if self.south is not None:
for k in range(self.nvars):
self.sim.u0[k].upload(self.sim.stream, self.in_s[k,:,:], extent=self.write_s)
#Wait for sending to complete
for comm in comm_send:
comm.wait()
def ew_download_before_exchange(self):
####
# Then transfer east-west including ghost cells that have been filled in by north-south transfer above
####
#Download from the GPU
if self.east is not None:
for k in range(self.nvars):
self.sim.u0[k].download(self.sim.stream, cpu_data=self.out_e[k,:,:], asynch=True, extent=self.read_e)
if self.west is not None:
for k in range(self.nvars):
self.sim.u0[k].download(self.sim.stream, cpu_data=self.out_w[k,:,:], asynch=True, extent=self.read_w)
self.sim.stream.synchronize()
def ew_do_exchange(self):
#Send/receive to east/west neighbours
comm_send = []
comm_recv = []
if self.east is not None:
comm_send += [self.grid.comm.Isend(self.out_e, dest=self.east, tag=4*self.nt + 2)]
comm_recv += [self.grid.comm.Irecv(self.in_e, source=self.east, tag=4*self.nt + 3)]
if self.west is not None:
comm_send += [self.grid.comm.Isend(self.out_w, dest=self.west, tag=4*self.nt + 3)]
comm_recv += [self.grid.comm.Irecv(self.in_w, source=self.west, tag=4*self.nt + 2)]
#Wait for incoming transfers to complete
for comm in comm_recv:
comm.wait()
def ew_upload_after_exchange(self):
#Upload to the GPU
if self.east is not None:
for k in range(self.nvars):
self.sim.u0[k].upload(self.sim.stream, self.in_e[k,:,:], extent=self.write_e)
if self.west is not None:
for k in range(self.nvars):
self.sim.u0[k].upload(self.sim.stream, self.in_w[k,:,:], extent=self.write_w)
#Wait for sending to complete
for comm in comm_send:
comm.wait()

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@ -32,9 +32,6 @@ class SHMEMGrid(object):
"""
Class which represents an SHMEM grid of GPUs. Facilitates easy communication between
neighboring subdomains in the grid. Contains one CUDA context per subdomain.
XXX: Adapted to debug on a single GPU. Either remove this possibility or
make it less hacky...
"""
def __init__(self, ngpus=None, ndims=2):
self.logger = logging.getLogger(__name__)
@ -44,13 +41,14 @@ class SHMEMGrid(object):
num_cuda_devices = cuda.Device.count()
if ngpus is None:
#ngpus = num_cuda_devices
ngpus = 2
ngpus = num_cuda_devices
# XXX: disabled for testing on single-GPU system
#assert ngpus <= num_cuda_devices, "Trying to allocate more GPUs than are available in the system."
assert ndims == 2, "Unsupported number of dimensions. Must be two at the moment"
#assert ngpus >= 2, "Must have at least two GPUs available to run multi-GPU simulations."
assert ndims == 2, "Unsupported number of dimensions. Must be two at the moment"
self.ngpus = ngpus
self.ndims = ndims
@ -59,10 +57,12 @@ class SHMEMGrid(object):
self.logger.debug("Created {:}-dimensional SHMEM grid, using {:} GPUs".format(
self.ndims, self.ngpus))
# XXX: Is this a natural place to store the contexts? Consider moving contexts out of this class.
# XXX: Is this a natural place to store the contexts? Consider moving contexts out of this
# class, into notebook / calling script (shmemTesting.py)
self.cuda_contexts = []
for i in range(self.ngpus):
# XXX: disabled for testing on single-GPU system
#self.cuda_contexts.append(CudaContext.CudaContext(device=i, autotuning=False))
self.cuda_contexts.append(CudaContext.CudaContext(device=0, autotuning=False))
@ -168,6 +168,13 @@ class SHMEMSimulatorGroup(Simulator.BaseSimulator):
self.sims = sims
# XXX: This is not what was intended. Do we need extra wrapper class SHMEMSimulator?
# See also getOutput() and check().
#
# SHMEMSimulatorGroup would then not have any superclass, but manage a collection of
# SHMEMSimulators that have BaseSimulator as a superclass.
#
# This would also eliminate the need for all the array bookkeeping in this class.
autotuner = sims[0].context.autotuner
sims[0].context.autotuner = None
boundary_conditions = sims[0].getBoundaryConditions()
@ -278,6 +285,7 @@ class SHMEMSimulatorGroup(Simulator.BaseSimulator):
def getOutput(self):
# XXX: Does not return what we would expect.
# Returns first subdomain, but we want the whole domain.
return self.sims[0].getOutput()
def synchronize(self):
@ -286,12 +294,14 @@ class SHMEMSimulatorGroup(Simulator.BaseSimulator):
def check(self):
# XXX: Does not return what we would expect.
# Checks only first subdomain, but we want to check the whole domain.
return self.sims[0].check()
def computeDt(self):
global_dt = float("inf")
# XXX: Global sync is needed here
for sim in self.sims:
sim.context.synchronize()
for sim in self.sims:
local_dt = sim.computeDt()
@ -322,8 +332,6 @@ class SHMEMSimulatorGroup(Simulator.BaseSimulator):
####
for i in range(len(self.sims)):
self.ns_download(i)
# XXX: Global sync is needed here
for i in range(len(self.sims)):
self.ns_upload(i)
@ -333,8 +341,6 @@ class SHMEMSimulatorGroup(Simulator.BaseSimulator):
####
for i in range(len(self.sims)):
self.ew_download(i)
# XXX: Global sync is needed here
for i in range(len(self.sims)):
self.ew_upload(i)
@ -343,10 +349,12 @@ class SHMEMSimulatorGroup(Simulator.BaseSimulator):
#Download from the GPU
if self.north[i] is not None:
for k in range(self.nvars[i]):
self.sims[i].u0[k].download(self.sims[i].stream, cpu_data=self.n[i][k,:,:], asynch=True, extent=self.read_n[i])
# XXX: Unnecessary global sync (only need to sync with neighboring subdomain to the north)
self.sims[i].u0[k].download(self.sims[i].stream, cpu_data=self.n[i][k,:,:], extent=self.read_n[i])
if self.south[i] is not None:
for k in range(self.nvars[i]):
self.sims[i].u0[k].download(self.sims[i].stream, cpu_data=self.s[i][k,:,:], asynch=True, extent=self.read_s[i])
# XXX: Unnecessary global sync (only need to sync with neighboring subdomain to the south)
self.sims[i].u0[k].download(self.sims[i].stream, cpu_data=self.s[i][k,:,:], extent=self.read_s[i])
self.sims[i].stream.synchronize()
def ns_upload(self, i):
@ -362,10 +370,12 @@ class SHMEMSimulatorGroup(Simulator.BaseSimulator):
#Download from the GPU
if self.east[i] is not None:
for k in range(self.nvars[i]):
self.sims[i].u0[k].download(self.sims[i].stream, cpu_data=self.e[i][k,:,:], asynch=True, extent=self.read_e[i])
# XXX: Unnecessary global sync (only need to sync with neighboring subdomain to the east)
self.sims[i].u0[k].download(self.sims[i].stream, cpu_data=self.e[i][k,:,:], extent=self.read_e[i])
if self.west[i] is not None:
for k in range(self.nvars[i]):
self.sims[i].u0[k].download(self.sims[i].stream, cpu_data=self.w[i][k,:,:], asynch=True, extent=self.read_w[i])
# XXX: Unnecessary global sync (only need to sync with neighboring subdomain to the west)
self.sims[i].u0[k].download(self.sims[i].stream, cpu_data=self.w[i][k,:,:], extent=self.read_w[i])
self.sims[i].stream.synchronize()
def ew_upload(self, i):

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@ -60,10 +60,11 @@ logger.info("File logger using level %s to %s", logging.getLevelName(log_level_f
####
# Initialize SHMEM grid etc
####
nsubdomains = 2
logger.info("Creating SHMEM grid")
grid = SHMEMSimulatorGroup.SHMEMGrid(ngpus=nsubdomains)
# XXX: need to explicitly set ngpus when testing on single-GPU system
grid = SHMEMSimulatorGroup.SHMEMGrid(ngpus=4)
@ -79,13 +80,6 @@ save_var_names = ['rho', 'rho_u', 'rho_v', 'E']
outfile = "shmem_out.nc"
#outfile[i] = "shmem_out_" + str(i) + ".nc"
#arguments = []
#local_sim = []
#sim = []
####
# Run simulation
####