我正在开发一个利用并行化的Jenkins管道。然而，我面临着一个问题，即并行阶段似乎彼此减慢，而不是实现真正的并行性。下面是我使用的代码：

pipeline {
  agent any
  stages {
    stage('Dependencies') {
      when {
        anyOf {
          branch 'develop';
          branch 'demo';
          branch 'test';
        }
      }
      parallel{
        stage('Cloud Libraries') {
          steps {
            sh "umask 0000;" 
            sh "pip3.8 install --no-cache-dir -r requirements/cloud.txt -t ${WORKSPACE}/layers/cloud_libraries/python/"
          }
        }
        stage('Cellect Data Processing') {
          steps {
            sh "umask 0000;" 
            sh "pip3.8 install --no-cache-dir -r requirements/cellect/data_processing.txt -t ${WORKSPACE}/layers/cellect_data_processing/python/"
          }
        }
        stage('Cellect Warranty Processing') {
          steps {
            sh "umask 0000;" 
            sh "pip3.8 install --no-cache-dir -r requirements/cellect/warranty_processing.txt -t ${WORKSPACE}/layers/cellect_warranty_processing/python/"
          }
        }
        stage('Cellect Data Consumer') {
          steps {
            sh "umask 0000;" 
            sh "pip3.8 install --no-cache-dir -r requirements/cellect/data_consumer.txt -t ${WORKSPACE}/layers/cellect_data_consumer/python/"
          }
        }
        stage('Cellect BESS Control') {
          steps {
            sh "umask 0000;" 
            sh "pip3.8 install --no-cache-dir -r requirements/cellect/bess_control.txt -t ${WORKSPACE}/layers/cellect_bess_control/python/"
          }
        }

      }
    }
  }
}

以前，当顺序执行阶段时，各个时间如下：15秒20秒20秒7秒5秒然而，在将它们并行化之后，时间变成了：17秒24秒49秒50秒44秒
虽然并行执行的总时间比顺序执行的时间长，但我认为不应该是这样。我是否遗漏了什么，或者对并行化的工作原理有错误的理解？