Reduce the compiling thread number

Signed-off-by: NJinHai-CN <hai.jin@zilliz.com>

ci/jenkins/step/build.groovy

@@ -4,9 +4,9 @@ timeout(time: 120, unit: 'MINUTES') {
             def checkResult = sh(script: "./check_ccache.sh -l ${params.JFROG_ARTFACTORY_URL}/ccache", returnStatus: true)
     
             if ("${BINARY_VERSION}" == "gpu") {
-                sh "/bin/bash --login -c \". ./before-install.sh && ./build.sh -t ${params.BUILD_TYPE} -j4 -i ${env.MILVUS_INSTALL_PREFIX} --with_fiu --coverage -l -g -u\""
+                sh "/bin/bash --login -c \". ./before-install.sh && ./build.sh -t ${params.BUILD_TYPE} -j3 -i ${env.MILVUS_INSTALL_PREFIX} --with_fiu --coverage -l -g -u\""
             } else {
-                sh "/bin/bash --login -c \". ./before-install.sh && ./build.sh -t ${params.BUILD_TYPE} -j4 -i ${env.MILVUS_INSTALL_PREFIX} --with_fiu --coverage -l -u\""
+                sh "/bin/bash --login -c \". ./before-install.sh && ./build.sh -t ${params.BUILD_TYPE} -j3 -i ${env.MILVUS_INSTALL_PREFIX} --with_fiu --coverage -l -u\""
             }
             sh "./update_ccache.sh -l ${params.JFROG_ARTFACTORY_URL}/ccache -u ${USERNAME} -p ${PASSWORD}"
         }