linux - NUMA 内存页面迁移开销

Question

我必须找出在 Linux 下与 NUMA 内存页面迁移相关的开销。

您能告诉我可以使用哪些工具吗？

如果可能的话，你能举个例子吗。

Answer 1

如果您想了解您的系统是否正在执行过多的远程节点内存访问并且您正在使用英特尔 CPU，Intel's PMU有一个名为 vtbwrun 的实用程序来报告 QPI/uncore 事件。

如果您想查看执行页面迁移需要多长时间，您可以测量调用 numa_move_pages 的持续时间(由 numactl 包提供)。

这是 an example :

/*
 * Test program to test the moving of a processes pages.
 *
 * (C) 2006 Silicon Graphics, Inc.
 *          Christoph Lameter <clameter@sgi.com>
 */
#include <stdio.h>
#include <stdlib.h>
#include "../numa.h"
#include <unistd.h>
#include <errno.h>

unsigned int pagesize;
unsigned int page_count = 32;

char *page_base;
char *pages;

void **addr;
int *status;
int *nodes;
int errors;
int nr_nodes;

struct bitmask *old_nodes;
struct bitmask *new_nodes;

int main(int argc, char **argv)
{
      int i, rc;

      pagesize = getpagesize();

      nr_nodes = numa_max_node()+1;

      old_nodes = numa_bitmask_alloc(nr_nodes);
        new_nodes = numa_bitmask_alloc(nr_nodes);
        numa_bitmask_setbit(old_nodes, 1);
        numa_bitmask_setbit(new_nodes, 0);

      if (nr_nodes < 2) {
            printf("A minimum of 2 nodes is required for this test.\n");
            exit(1);
      }

      setbuf(stdout, NULL);
      printf("migrate_pages() test ......\n");
      if (argc > 1)
            sscanf(argv[1], "%d", &page_count);

      page_base = malloc((pagesize + 1) * page_count);
      addr = malloc(sizeof(char *) * page_count);
      status = malloc(sizeof(int *) * page_count);
      nodes = malloc(sizeof(int *) * page_count);
      if (!page_base || !addr || !status || !nodes) {
            printf("Unable to allocate memory\n");
            exit(1);
      }

      pages = (void *) ((((long)page_base) & ~((long)(pagesize - 1))) + pagesize);

      for (i = 0; i < page_count; i++) {
            if (i != 2)
                  /* We leave page 2 unallocated */
                  pages[ i * pagesize ] = (char) i;
            addr[i] = pages + i * pagesize;
            nodes[i] = 1;
            status[i] = -123;
      }

      /* Move to starting node */
      rc = numa_move_pages(0, page_count, addr, nodes, status, 0);
      if (rc < 0 && errno != ENOENT) {
            perror("move_pages");
            exit(1);
      }

      /* Verify correct startup locations */
      printf("Page location at the beginning of the test\n");
      printf("------------------------------------------\n");

      numa_move_pages(0, page_count, addr, NULL, status, 0);
      for (i = 0; i < page_count; i++) {
            printf("Page %d vaddr=%p node=%d\n", i, pages + i * pagesize, status[i]);
            if (i != 2 && status[i] != 1) {
                  printf("Bad page state before migrate_pages. Page %d status %d\n",i, status[i]);
                  exit(1);
            }
      }

      /* Move to node zero */
      numa_move_pages(0, page_count, addr, nodes, status, 0);

      printf("\nMigrating the current processes pages ...\n");
      rc = numa_migrate_pages(0, old_nodes, new_nodes);

      if (rc < 0) {
            perror("numa_migrate_pages failed");
            errors++;
      }

      /* Get page state after migration */
      numa_move_pages(0, page_count, addr, NULL, status, 0);
      for (i = 0; i < page_count; i++) {
            printf("Page %d vaddr=%lx node=%d\n", i,
                  (unsigned long)(pages + i * pagesize), status[i]);
            if (i != 2) {
                  if (pages[ i* pagesize ] != (char) i) {
                        printf("*** Page contents corrupted.\n");
                        errors++;
                  } else if (status[i]) {
                        printf("*** Page on the wrong node\n");
                        errors++;
                  }
            }
      }

      if (!errors)
            printf("Test successful.\n");
      else
            printf("%d errors.\n", errors);

      return errors > 0 ? 1 : 0;
}