关于 fio 延迟指标的选择和计算

[tpxcer]

是这样的，我写了 fio 测试脚本，然后有观众提议放个读写延迟上去。我现在有点纠结应该放哪个数值. 我打算取"lat_ns"的"mean" 也就是值 2718863.941184 。 不知道这个是否合理？ 这个值我要不要再除以 11292449 ？有点噶住了

{
      "jobname" : "read,RND4K-Q32T16",
      "groupid" : 10,
      "error" : 0,
      "eta" : 0,
      "elapsed" : 786,
      "job options" : {
        "name" : "read,RND4K-Q32T16",
        "rw" : "randread",
        "iodepth" : "32",
        "bs" : "4k",
        "numjobs" : "16"
      },
      "read" : {
        "io_bytes" : 46253879296,
        "io_kbytes" : 45169804,
        "bw_bytes" : 770782370,
        "bw" : 752717,
        "iops" : 188170.991018,
        "runtime" : 60009,
        "total_ios" : 11291953,
        "short_ios" : 0,
        "drop_ios" : 0,
        "slat_ns" : {
          "min" : 1780,
          "max" : 19582823,
          "mean" : 11969.273414,
          "stddev" : 18417.052843,
          "N" : 11291955
        },
        "clat_ns" : {
          "min" : 74196,
          "max" : 35534486,
          "mean" : 2706894.667020,
          "stddev" : 1860837.645574,
          "N" : 11292449,
          "percentile" : {
            "1.000000" : 522240,
            "5.000000" : 716800,
            "10.000000" : 888832,
            "20.000000" : 1187840,
            "30.000000" : 1499136,
            "40.000000" : 1843200,
            "50.000000" : 2211840,
            "60.000000" : 2670592,
            "70.000000" : 3194880,
            "80.000000" : 3948544,
            "90.000000" : 5210112,
            "95.000000" : 6520832,
            "99.000000" : 8847360,
            "99.500000" : 9633792,
            "99.900000" : 11730944,
            "99.950000" : 13565952,
            "99.990000" : 20578304
          }
        },
        "lat_ns" : {
          "min" : 228921,
          "max" : 35536822,
          "mean" : 2718863.941184,
          "stddev" : 1860842.689662,
          "N" : 11292449
        },
        "bw_min" : 697879,
        "bw_max" : 810166,
        "bw_agg" : 100.000000,
        "bw_mean" : 753568.975000,
        "bw_dev" : 1207.788641,
        "bw_samples" : 1920,
        "iops_min" : 174463,
        "iops_max" : 202538,
        "iops_mean" : 188389.150000,
        "iops_stddev" : 301.956112,
        "iops_samples" : 1920
      },
      。。。。。
    },

[samhjn]

不需要，这个数据就是这么多个 io 的平均端到端延迟。但是如果是关注延迟，建议测单路。