On 4/27/21 23:14, Gioh Kim wrote: > The IO performance test with fio after removing the likely and > unlikely macros in all if-statement shows no performance drop. > They do not help for the performance of rnbd. > > The fio test did random read on 32 rnbd devices and 64 processes. > Test environment: > - AMD Opteron(tm) Processor 6386 SE > - 125G memory > - kernel version: 5.4.86 why 5.4 and not linux-block/for-next ? > - gcc version: gcc (Debian 8.3.0-6) 8.3.0 > - Infiniband controller: InfiniBand: Mellanox Technologies MT26428 > [ConnectX VPI PCIe 2.0 5GT/s - IB QDR / 10GigE] (rev b0) > > before > read: IOPS=549k, BW=2146MiB/s > read: IOPS=544k, BW=2125MiB/s > read: IOPS=553k, BW=2158MiB/s > read: IOPS=535k, BW=2089MiB/s > read: IOPS=543k, BW=2122MiB/s > read: IOPS=552k, BW=2154MiB/s > average: IOPS=546k, BW=2132MiB/s > > after > read: IOPS=556k, BW=2172MiB/s > read: IOPS=561k, BW=2191MiB/s > read: IOPS=552k, BW=2156MiB/s > read: IOPS=551k, BW=2154MiB/s > read: IOPS=562k, BW=2194MiB/s > ----------- > average: IOPS=556k, BW=2173MiB/s > > The IOPS and bandwidth got better slightly after removing > likely/unlikely. (IOPS= +1.8% BW= +1.9%) But we cannot make sure > that removing the likely/unlikely help the performance because it > depends on various situations. We only make sure that removing the > likely/unlikely does not drop the performance. Did you get a chance to collect perf numbers to see which functions are getting faster ?
