我有一个Python脚本，它将:
我决定制作此脚本的新版本以加快处理速度。我的新脚本可以:
我创建的代码存在一些问题。
我认为解决这个问题不需要ROS知识。我是否正确使用多处理库？
import glob
import os
import argparse
from datetime import datetime
import numpy as np
import cv2
import sys
import copy
import rosbag
import rospy
from sensor_msgs.msg import CompressedImage
from cv_bridge import CvBridge
from multiprocessing import Process, Manager, Queue, cpu_count, queues
# Image constants
IMG_W = 1280
IMG_H = 1024
NUM_CHANNEL = 3
bridge = CvBridge()
parser = argparse.ArgumentParser(
description='Creates a bag containing the image data')
parser.add_argument(
'input_dirs',
nargs='+',
help='Input and Output directory for bag files.')
args = parser.parse_args()
queue = Queue()
manager = Manager()
converted_imgs = manager.list()
bag_path=''
out_path=''
if len(args.input_dirs) == 2:
bag_path = args.input_dirs[0]
out_path = args.input_dirs[1]
os.chdir(bag_path)
else:
print('Please enter the input and output bag path.')
exit()
bag_names = []
# Add all bags in bag_path to bag_names
for file in sorted(os.listdir(bag_path)):
if file.endswith(".bag"):
bag_names.append(file)
camera_image_topics = {
'/cam_a/image_raw': '/cam_a/compressed',
'/cam_b/image_raw': '/cam_b/compressed',
'/cam_c/image_raw': '/cam_c/compressed'
}
# Display progress function
# Prints out the current progress on the same line
def display_progress(progress):
sys.stdout.write("\r" + 'PROGRESS ' + format(progress, '.2f') + '%')
sys.stdout.flush()
# Convert each Image to CompressedImage
def create_msg(img_total):
global queue
global converted_imgs
while not queue.empty():
topic, raw_data, t = queue.get()
# Display progress
progress = ((img_total - queue.qsize()) * 100.00) / img_total
display_progress(progress)
# Create CompressedImage msg and compress the image
cmprs_msg = CompressedImage()
cmprs_msg.format = "png"
cmprs_msg.data = np.array(cv2.imencode('.png', raw_data, [int(cv2.IMWRITE_PNG_COMPRESSION), 3])[1]).tostring()
cmprs_msg.header.stamp = t
# Add message to be written to the outbag
converted_imgs.append((topic, cmprs_msg))
return
for i in range(len(bag_names)):
print('Reading bag ' + bag_names[i])
with rosbag.Bag(out_path + 'compressed_' + bag_names[i], 'w') as outbag:
count = 0.0 # Init as float
msg_total = rosbag.Bag(bag_names[i]).get_message_count()
print('Copying non image ros messages into outbag,')
print('also adding image messages to the queue')
# print('Copying msgs and compressing images into outbag.')
for topic, msg, t in rosbag.Bag(bag_names[i]).read_messages():
if topic not in camera_image_topics:
outbag.write(topic, msg, t)
else:
# Convert image data to numpy matrix and add to queue
cv2_matrix = bridge.imgmsg_to_cv2(msg, msg.encoding)
raw_data = np.asarray(cv2_matrix).reshape((IMG_H, IMG_W, NUM_CHANNEL))
queue.put((camera_image_topics[topic], raw_data, t))
# Increase count of finished messages
count += 1
# Display progress
progress = (count/msg_total) * 100
display_progress(progress)
# Finished
print(' [DONE]')
img_total = queue.qsize()
print('Compressing images within the queue')
processes = []
for cpu_num in xrange(cpu_count()):
p = Process(target=create_msg, args=(img_total,))
processes.append(p)
for p in processes:
p.start()
# Finished
for p in processes:
p.join()
print(' [DONE]')
print('Adding images to the outbag')
for topic, msg in converted_imgs:
outbag.write(topic, msg, msg.header.stamp)
更新1:按要求提供MVP。似乎使用了所有核心...
from multiprocessing import Process, Manager, Queue, cpu_count, queues
queue = Queue()
manager = Manager()
converted_imgs = manager.list()
# Convert each Image to CompressedImage
def create_msg(img_total):
global queue
global converted_imgs
while not queue.empty():
x = queue.get()
# Add message to be written to the outbag
converted_imgs.append(x ** 2)
return
print('Add to queue')
for x in range(0, 100000):
queue.put(10)
img_total = queue.qsize()
print('Calculate square of each queue member')
processes = []
for cpu_num in xrange(cpu_count()):
p = Process(target=create_msg, args=(img_total,))
processes.append(p)
for p in processes:
p.start()
# Finished
for p in processes:
p.join()
print(' [DONE]')
print('Adding images to the outbag')
for x in converted_imgs:
print(x)
更新2:我认为我编写的代码是正确的。正如罗斯在评论中所说，它很可能在队列中序列化。我添加了评论以确认他写了什么。似乎只使用了两个进程，然后下降到一个。我认为对象太大，无法使程序具有多个进程。
Copying non image ros messages into outbag,
also adding image messages to the queue
PROGRESS 100.00% [DONE]
Compressing images within the queue
Process 0
Process: 0 Queue size: 1472
Process 1
Process 2
Process: 2 Queue size: 1471
Process 3
Process: 0 Queue size: 1470
Process: 2 Queue size: 1469
Process: 0 Queue size: 1468
Process: 2 Queue size: 1467
Process: 0 Queue size: 1466
Process: 2 Queue size: 1465
Process: 0 Queue size: 1464
Process: 2 Queue size: 1463
Process: 0 Queue size: 1462
Process: 2 Queue size: 1461
Process: 0 Queue size: 1460
Process: 2 Queue size: 1459
Process: 0 Queue size: 1458
Process: 2 Queue size: 1457
Process: 0 Queue size: 1456
Process: 2 Queue size: 1455
Process: 0 Queue size: 1454
Process: 2 Queue size: 1453
Process: 0 Queue size: 1452
Process: 2 Queue size: 1451
Process: 0 Queue size: 1450
Process: 2 Queue size: 1449
Process: 0 Queue size: 1448
Process: 2 Queue size: 1447
Process: 0 Queue size: 1446
Process: 2 Queue size: 1445
Process: 0 Queue size: 1444
Process: 2 Queue size: 1443
Process: 0 Queue size: 1442
Process: 2 Queue size: 1441
Process: 0 Queue size: 1440
Process: 2 Queue size: 1439
Process: 0 Queue size: 1438
Process: 2 Queue size: 1437
Process: 0 Queue size: 1436
Process: 2 Queue size: 1435
Process: 0 Queue size: 1434
Process: 2 Queue size: 1433
Process: 0 Queue size: 1432
Process: 2 Queue size: 1431
Process: 0 Queue size: 1430
Process: 2 Queue size: 1429
Process: 0 Queue size: 1428
Process: 2 Queue size: 1427
Process: 0 Queue size: 1426
Process: 2 Queue size: 1425
Process: 0 Queue size: 1424
Process: 2 Queue size: 1423
Process: 0 Queue size: 1422
Process: 2 Queue size: 1421
Process: 0 Queue size: 1420
Process: 2 Queue size: 1419
Process: 0 Queue size: 1418
Process: 2 Queue size: 1417
Process: 0 Queue size: 1416
Process: 2 Queue size: 1415
Process: 0 Queue size: 1414
Process: 2 Queue size: 1413
Process: 0 Queue size: 1412
Process: 2 Queue size: 1411
Process: 0 Queue size: 1410
Process: 2 Queue size: 1409
Process: 0 Queue size: 1408
Process: 2 Queue size: 1407
Process: 0 Queue size: 1406
Process: 2 Queue size: 1405
Process: 0 Queue size: 1404
Process: 2 Queue size: 1403
Process: 0 Queue size: 1402
Process: 2 Queue size: 1401
Process: 0 Queue size: 1400
Process: 2 Queue size: 1399
Process: 0 Queue size: 1398
Process: 2 Queue size: 1397
Process: 0 Queue size: 1396
Process: 2 Queue size: 1395
Process: 0 Queue size: 1394
Process: 2 Queue size: 1393
Process: 0 Queue size: 1392
Process: 2 Queue size: 1391
Process: 0 Queue size: 1390
Process: 2 Queue size: 1389
Process: 0 Queue size: 1388
Process: 2 Queue size: 1387
Process: 0 Queue size: 1386
Process: 2 Queue size: 1385
Process: 0 Queue size: 1384
Process: 2 Queue size: 1383
Process: 0 Queue size: 1382
Process: 2 Queue size: 1381
Process: 0 Queue size: 1380
Process: 2 Queue size: 1379
Process: 0 Queue size: 1378
Process: 2 Queue size: 1377
Process: 0 Queue size: 1376
Process: 2 Queue size: 1375
Process: 0 Queue size: 1374
Process: 2 Queue size: 1373
Process: 0 Queue size: 1372
Process: 2 Queue size: 1371
Process: 0 Queue size: 1370
Process: 2 Queue size: 1369
Process: 0 Queue size: 1368
Process: 2 Queue size: 1367
Process: 0 Queue size: 1366
Process: 2 Queue size: 1365
Process: 0 Queue size: 1364
Process: 2 Queue size: 1363
Process: 0 Queue size: 1362
Process: 2 Queue size: 1361
Process: 0 Queue size: 1360
Process: 2 Queue size: 1359
Process: 0 Queue size: 1358
Process: 2 Queue size: 1357
Process: 0 Queue size: 1356
Process: 2 Queue size: 1355
Process: 0 Queue size: 1354
Process: 2 Queue size: 1353
Process: 0 Queue size: 1352
Process: 2 Queue size: 1351
Process: 0 Queue size: 1350
Process: 2 Queue size: 1349
Process: 0 Queue size: 1348
Process: 2 Queue size: 1347
Process: 0 Queue size: 1346
Process: 2 Queue size: 1345
Process: 0 Queue size: 1344
Process: 2 Queue size: 1343
Process: 0 Queue size: 1342
Process: 2 Queue size: 1341
Process: 0 Queue size: 1340
Process: 2 Queue size: 1339
Process: 0 Queue size: 1338
Process: 2 Queue size: 1337
Process: 0 Queue size: 1336
Process: 2 Queue size: 1335
Process: 0 Queue size: 1334
Process: 2 Queue size: 1333
Process: 0 Queue size: 1332
Process: 2 Queue size: 1331
Process: 0 Queue size: 1330
Process: 2 Queue size: 1329
Process: 0 Queue size: 1328
Process: 2 Queue size: 1327
Process: 0 Queue size: 1326
Process: 2 Queue size: 1325
Process: 0 Queue size: 1324
Process: 2 Queue size: 1323
Process: 0 Queue size: 1322
Process: 2 Queue size: 1321
Process: 0 Queue size: 1320
Process: 2 Queue size: 1319
Process: 0 Queue size: 1318
Process: 2 Queue size: 1317
Process: 0 Queue size: 1316
Process: 2 Queue size: 1315
Process: 0 Queue size: 1314
Process: 2 Queue size: 1313
Process: 0 Queue size: 1312
Process: 2 Queue size: 1311
Process: 0 Queue size: 1310
Process: 2 Queue size: 1309
Process: 0 Queue size: 1308
Process: 2 Queue size: 1307
Process: 0 Queue size: 1306
Process: 2 Queue size: 1305
Process: 0 Queue size: 1304
Process: 2 Queue size: 1303
Process: 0 Queue size: 1302
Process: 2 Queue size: 1301
Process: 0 Queue size: 1300
Process: 2 Queue size: 1299
Process: 0 Queue size: 1298
Process: 2 Queue size: 1297
Process: 0 Queue size: 1296
Process: 2 Queue size: 1295
Process: 0 Queue size: 1294
Process: 2 Queue size: 1293
Process: 0 Queue size: 1292
Process: 2 Queue size: 1291
Process: 0 Queue size: 1290
Process: 2 Queue size: 1289
Process: 0 Queue size: 1288
Process: 2 Queue size: 1287
Process: 0 Queue size: 1286
Process: 2 Queue size: 1285
Process: 0 Queue size: 1284
Process: 2 Queue size: 1283
Process: 0 Queue size: 1282
Process: 2 Queue size: 1281
Process: 0 Queue size: 1280
Process: 2 Queue size: 1279
Process: 0 Queue size: 1278
Process: 2 Queue size: 1277
Process: 0 Queue size: 1276
Process: 2 Queue size: 1275
Process: 0 Queue size: 1274
Process: 2 Queue size: 1273
Process: 0 Queue size: 1272
Process: 2 Queue size: 1271
Process: 0 Queue size: 1270
Process: 2 Queue size: 1269
Process: 0 Queue size: 1268
Process: 2 Queue size: 1267
Process: 0 Queue size: 1266
Process: 2 Queue size: 1265
Process: 0 Queue size: 1264
Process: 2 Queue size: 1263
Process: 0 Queue size: 1262
Process: 2 Queue size: 1261
Process: 0 Queue size: 1260
Process: 2 Queue size: 1259
Process: 0 Queue size: 1258
Process: 2 Queue size: 1257
Process: 0 Queue size: 1256
Process: 2 Queue size: 1255
Process: 0 Queue size: 1254
Process: 2 Queue size: 1253
Process: 0 Queue size: 1252
Process: 2 Queue size: 1251
Process: 0 Queue size: 1250
Process: 2 Queue size: 1249
Process: 0 Queue size: 1248
Process: 2 Queue size: 1247
Process: 0 Queue size: 1246
Process: 2 Queue size: 1245
Process: 0 Queue size: 1244
Process: 2 Queue size: 1243
Process: 0 Queue size: 1242
Process: 2 Queue size: 1241
Process: 0 Queue size: 1240
Process: 2 Queue size: 1239
Process: 0 Queue size: 1238
Process: 2 Queue size: 1237
Process: 0 Queue size: 1236
Process: 2 Queue size: 1235
Process: 0 Queue size: 1234
Process: 2 Queue size: 1233
Process: 0 Queue size: 1232
Process: 2 Queue size: 1231
Process: 0 Queue size: 1230
Process: 2 Queue size: 1229
Process: 0 Queue size: 1228
Process: 2 Queue size: 1227
Process: 0 Queue size: 1226
Process: 2 Queue size: 1225
Process: 0 Queue size: 1224
Process: 2 Queue size: 1223
Process: 0 Queue size: 1222
Process: 2 Queue size: 1221
Process: 0 Queue size: 1220
Process: 2 Queue size: 1219
Process: 0 Queue size: 1218
Process: 2 Queue size: 1217
Process: 0 Queue size: 1216
Process: 2 Queue size: 1215
Process: 0 Queue size: 1214
Process: 2 Queue size: 1213
Process: 0 Queue size: 1212
Process: 2 Queue size: 1211
Process: 0 Queue size: 1210
Process: 2 Queue size: 1209
Process: 0 Queue size: 1208
Process: 2 Queue size: 1207
Process: 0 Queue size: 1206
Process: 2 Queue size: 1205
Process: 0 Queue size: 1204
Process: 2 Queue size: 1203
Process: 0 Queue size: 1202
Process: 2 Queue size: 1201
Process: 0 Queue size: 1200
Process: 2 Queue size: 1199
Process: 0 Queue size: 1198
Process: 2 Queue size: 1197
Process: 0 Queue size: 1196
Process: 2 Queue size: 1195
Process: 0 Queue size: 1194
Process: 2 Queue size: 1193
Process: 0 Queue size: 1192
Process: 2 Queue size: 1191
Process: 0 Queue size: 1190
Process: 2 Queue size: 1189
Process: 0 Queue size: 1188
Process: 2 Queue size: 1187
Process: 0 Queue size: 1186
Process: 2 Queue size: 1185
Process: 0 Queue size: 1184
Process: 2 Queue size: 1183
Process: 0 Queue size: 1182
Process: 2 Queue size: 1181
Process: 0 Queue size: 1180
Process: 2 Queue size: 1179
Process: 0 Queue size: 1178
Process: 2 Queue size: 1177
Process: 0 Queue size: 1176
Process: 2 Queue size: 1175
Process: 0 Queue size: 1174
Process: 2 Queue size: 1173
Process: 0 Queue size: 1172
Process: 2 Queue size: 1171
Process: 0 Queue size: 1170
Process: 2 Queue size: 1169
Process: 0 Queue size: 1168
Process: 2 Queue size: 1167
Process: 0 Queue size: 1166
Process: 2 Queue size: 1165
Process: 0 Queue size: 1164
Process: 2 Queue size: 1163
Process: 0 Queue size: 1162
Process: 2 Queue size: 1161
Process: 0 Queue size: 1160
Process: 2 Queue size: 1159
Process: 0 Queue size: 1158
Process: 2 Queue size: 1157
Process: 0 Queue size: 1156
Process: 2 Queue size: 1155
Process: 0 Queue size: 1154
Process: 2 Queue size: 1153
Process: 0 Queue size: 1152
Process: 2 Queue size: 1151
Process: 0 Queue size: 1150
Process: 2 Queue size: 1149
Process: 0 Queue size: 1148
Process: 2 Queue size: 1147
Process: 0 Queue size: 1146
Process: 2 Queue size: 1145
Process: 0 Queue size: 1144
Process: 2 Queue size: 1143
Process: 0 Queue size: 1142
Process: 2 Queue size: 1141
Process: 0 Queue size: 1140
Process: 2 Queue size: 1139
Process: 0 Queue size: 1138
Process: 2 Queue size: 1137
Process: 0 Queue size: 1136
Process: 2 Queue size: 1135
Process: 0 Queue size: 1134
Process: 2 Queue size: 1133
Process: 0 Queue size: 1132
Process: 2 Queue size: 1131
Process: 0 Queue size: 1130
Process: 2 Queue size: 1129
Process: 0 Queue size: 1128
Process: 2 Queue size: 1127
Process: 0 Queue size: 1126
Process: 2 Queue size: 1125
Process: 0 Queue size: 1124
Process: 2 Queue size: 1123
Process: 0 Queue size: 1122
Process: 2 Queue size: 1121
Process: 0 Queue size: 1120
Process: 2 Queue size: 1119
Process: 0 Queue size: 1118
Process: 2 Queue size: 1117
Process: 0 Queue size: 1116
Process: 2 Queue size: 1115
Process: 0 Queue size: 1114
Process: 2 Queue size: 1113
Process: 0 Queue size: 1112
Process: 2 Queue size: 1111
Process: 0 Queue size: 1110
Process: 2 Queue size: 1109
Process: 0 Queue size: 1108
Process: 2 Queue size: 1107
Process: 0 Queue size: 1106
Process: 2 Queue size: 1105
Process: 0 Queue size: 1104
Process: 2 Queue size: 1103
Process: 0 Queue size: 1102
Process: 2 Queue size: 1101
Process: 0 Queue size: 1100
Process: 2 Queue size: 1099
Process: 0 Queue size: 1098
Process: 2 Queue size: 1097
Process: 0 Queue size: 1096
Process: 2 Queue size: 1095
Process: 0 Queue size: 1094
Process: 2 Queue size: 1093
Process: 0 Queue size: 1092
Process: 2 Queue size: 1091
Process: 0 Queue size: 1090
Process: 2 Queue size: 1089
Process: 0 Queue size: 1088
Process: 2 Queue size: 1087
Process: 0 Queue size: 1086
Process: 2 Queue size: 1085
Process: 0 Queue size: 1084
Process: 2 Queue size: 1083
Process: 0 Queue size: 1082
Process: 2 Queue size: 1081
Process: 0 Queue size: 1080
Process: 2 Queue size: 1079
Process: 0 Queue size: 1078
Process: 2 Queue size: 1077
Process: 0 Queue size: 1076
Process: 2 Queue size: 1075
Process: 0 Queue size: 1074
Process: 2 Queue size: 1073
Process: 0 Queue size: 1072
Process: 2 Queue size: 1071
Process: 0 Queue size: 1070
Process: 2 Queue size: 1069
Process: 0 Queue size: 1068
Process: 2 Queue size: 1067
Process: 0 Queue size: 1066
Process: 2 Queue size: 1065
Process: 0 Queue size: 1064
Process: 2 Queue size: 1063
Process: 0 Queue size: 1062
Process: 2 Queue size: 1061
Process: 0 Queue size: 1060
Process: 2 Queue size: 1059
Process: 0 Queue size: 1058
Process: 2 Queue size: 1057
Process: 0 Queue size: 1056
Process: 2 Queue size: 1055
Process: 0 Queue size: 1054
Process: 2 Queue size: 1053
Process: 0 Queue size: 1052
Process: 2 Queue size: 1051
Process: 2 Queue size: 1050
Process: 2 Queue size: 1049
Process: 2 Queue size: 1048
Process: 2 Queue size: 1047
Process: 2 Queue size: 1046
Process: 2 Queue size: 1045
Process: 2 Queue size: 1044
Process: 2 Queue size: 1043
Process: 2 Queue size: 1042
Process: 2 Queue size: 1041
Process: 2 Queue size: 1040
Process: 2 Queue size: 1039
Process: 2 Queue size: 1038
Process: 2 Queue size: 1037
Process: 2 Queue size: 1036
Process: 2 Queue size: 1035
Process: 2 Queue size: 1034
Process: 2 Queue size: 1033
Process: 2 Queue size: 1032
Process: 2 Queue size: 1031
Process: 2 Queue size: 1030
Process: 2 Queue size: 1029
Process: 2 Queue size: 1028
Process: 2 Queue size: 1027
Process: 2 Queue size: 1026
Process: 2 Queue size: 1025
Process: 2 Queue size: 1024
Process: 2 Queue size: 1023
Process: 2 Queue size: 1022
Process: 2 Queue size: 1021
Process: 2 Queue size: 1020
Process: 2 Queue size: 1019
Process: 2 Queue size: 1018
Process: 2 Queue size: 1017
Process: 2 Queue size: 1016
Process: 2 Queue size: 1015
Process: 2 Queue size: 1014
Process: 2 Queue size: 1013
Process: 2 Queue size: 1012
Process: 2 Queue size: 1011
Process: 2 Queue size: 1010
Process: 2 Queue size: 1009
Process: 2 Queue size: 1008
Process: 2 Queue size: 1007
Process: 2 Queue size: 1006
Process: 2 Queue size: 1005
Process: 2 Queue size: 1004
Process: 2 Queue size: 1003
Process: 2 Queue size: 1002
Process: 2 Queue size: 1001
Process: 2 Queue size: 1000
Process: 2 Queue size: 999
Process: 2 Queue size: 998
Process: 2 Queue size: 997
Process: 2 Queue size: 996
Process: 2 Queue size: 995
Process: 2 Queue size: 994
Process: 2 Queue size: 993
Process: 2 Queue size: 992
Process: 2 Queue size: 991
Process: 2 Queue size: 990
Process: 2 Queue size: 989
Process: 2 Queue size: 988
Process: 2 Queue size: 987
Process: 2 Queue size: 986
Process: 2 Queue size: 985
Process: 2 Queue size: 984
Process: 2 Queue size: 983
Process: 2 Queue size: 982
Process: 2 Queue size: 981
Process: 2 Queue size: 980
Process: 2 Queue size: 979
Process: 2 Queue size: 978
Process: 2 Queue size: 977
Process: 2 Queue size: 976
Process: 2 Queue size: 975
Process: 2 Queue size: 974
Process: 2 Queue size: 973
Process: 2 Queue size: 972
Process: 2 Queue size: 971
Process: 2 Queue size: 970
Process: 2 Queue size: 969
Process: 2 Queue size: 968
Process: 2 Queue size: 967
Process: 2 Queue size: 966
Process: 2 Queue size: 965
Process: 2 Queue size: 964
Process: 2 Queue size: 963
Process: 2 Queue size: 962
Process: 2 Queue size: 961
Process: 2 Queue size: 960
Process: 2 Queue size: 959
Process: 2 Queue size: 958
Process: 2 Queue size: 957
Process: 2 Queue size: 956
Process: 2 Queue size: 955
Process: 2 Queue size: 954
Process: 2 Queue size: 953
...
Process: 2 Queue size: 16
Process: 2 Queue size: 15
Process: 2 Queue size: 14
Process: 2 Queue size: 13
Process: 2 Queue size: 12
Process: 2 Queue size: 11
Process: 2 Queue size: 10
Process: 2 Queue size: 9
Process: 2 Queue size: 8
Process: 2 Queue size: 7
Process: 2 Queue size: 6
Process: 2 Queue size: 5
Process: 2 Queue size: 4
Process: 2 Queue size: 3
Process: 2 Queue size: 2
Process: 2 Queue size: 1
Process: 2 Queue size: 0
[DONE]
最佳答案
我对全局，队列和进程之间的交互方式并不特别熟悉，但是看起来这可能是您的瓶颈。尝试让您的进程通过管道将值返回到主线程!
# Convert each Image to CompressedImage
def create_msg(img_total, pipe):
# You won't need these:
# global queue
# global converted_imgs
while not YOUR_COUNTER():
x = queue.get()
# Add message to be written to the outbag
pipe.send(x ** 2)
return
# create a list to keep all processes
processes = []
# create a list to keep connections
parent_connections = []
for j in range(cpu_count()):
# create a pipe for communication
parent_conn, child_conn = Pipe()
parent_connections.append(parent_conn)
process_args = (YOUR_ARGS, child_conn)
# create the process, pass instance and connection
process = Process(target=create_msg, args=(process_args,))
processes.append(process)
# start all processes
for process in processes:
process.start()
# make sure that all processes have finished
for process in processes:
process.join()
for parent_connection in parent_connections:
while parent_connection.poll():
recv = parent_connection.recv()
# Redefine this list somewhere else to use
converted_imgs.append(recv)
关于python - Python多处理图像压缩-100％时只有一个CPU，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/49683473/