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我有一个PySpark的示例工作,它是PageRank算法的一个版本。 代码如下:PySpark速度Ubuntu vs Windows
from __future__ import print_function
from operator import add
import timeit
from pyspark.sql import SparkSession
# Normalize a list of pairs(url, rank) to 1
def normalize(ranks):
norm = sum([rank for u, rank in ranks])
ranks = [(u, rank/norm) for (u, rank) in ranks ]
return sorted(ranks, key=lambda x: x[1], reverse=True)
def pagerank_2(edgeList, n, niter):
# Loads all URLs from input file and initialize their neighbors.
m = edgeList.groupByKey().cache()
s = 0.85
# Loads all URLs with other URL(s) link to from input file
# and initialize ranks of them to one.
q = spark.sparkContext.range(n).map(lambda x: (x, 1.0)).cache()
r = spark.sparkContext.range(n).map(lambda x: (x, 0.0)).cache()
# Calculates and updates URL ranks continuously
# using PageRank algorithm.
for iteration in range(niter):
# Calculates URL contributions to the rank of other URLs.
# Add URL ranks based on neighbor contributions.
# Do not forget to add missing values in q and set to 0.0
q = q.fullOuterJoin(m)\
.flatMap(lambda x: (x[1][1] and [(u, x[1][0]/len(x[1][1])) for u in x[1][1]]) or [])\
.reduceByKey(add)\
.rightOuterJoin(r)\
.mapValues(lambda x: (x[0] or 0)*s + (1-s))
print("iteration = ", iteration)
# Collects all URL ranks and dump them to console after normalization
ranks = normalize(q.collect())
print(ranks[0:10])
if __name__ == "__main__":
spark = SparkSession\
.builder\
.master('local[*]')\
.appName("SparkPageRank")\
.config('spark.driver.allowMultipleContexts', 'true')\
.config('spark.sql.warehouse.dir', 'file:///C:/Home/Org/BigData/python/BE4/') \
.config('spark.sql.shuffle.partitions', '10')\
.getOrCreate()
spark.sparkContext.setLogLevel('WARN')
g = [(0, 1), (0, 5), (1, 2), (1, 3), (2, 3),
(2, 4), (2, 5), (3, 0), (5, 0), (5, 2)]
n = 6
edgeList = spark.sparkContext.parallelize(g)
print(timeit.timeit('pagerank_2(edgeList, 6, 10)', number=1, globals=globals()))
节点编号从0到n-1。 edgeList参数是一个RDD,它包含一对节点对(也称为边)。
我在本地模式下在Windows 10(Anaconda,Spark 2.1.0,winutils)上运行它。 这项工作分配为2896个任务,都非常轻。
我的问题是运行时间。 以上例为:
- Windows 10:> 40mn!
- 视窗子系统用于Linux(Ubuntu的14.04):30秒
该计算机是便携式计算机核心i7-4702HQ,16GB内存,512GB SSD。 当谈到启动过程时,Windows比Linux慢,但速度慢了50倍?肯定要做些什么来缩小这个差距?
我已禁用的Windows Defender为所有处于危险中的文件:java目录,蟒蛇目录等 要看看任何其他的想法?
感谢您的任何线索。
我不这么认为。这台机器上有8个内核,接近于10.无论如何,相同的参数适用于Windows和Ubuntu/WSL。 – FabPop