最重要的一篇paper：

A Top-Down method for performance analysis and counters architecture

这篇文章提出了topdown分析模型，可以视系统为一个黑盒，看出它是CPU bound还是memory bound的系统。

当然，perf stat命令也提供了相应的支持：

# perf stat --topdown^C Performance counter stats for 'system wide':
                                    retiring      bad speculation       frontend bound        backend bound S0-D0-C0           2                22.9%                 2.0%                27.9%                47.2% S0-D0-C1           2                10.7%                 0.0%                 0.0%                89.2% S0-D0-C2           2                10.7%                 0.0%                 0.0%                89.2% S0-D0-C3           2                11.6%                 3.4%                39.5%                45.5% S0-D0-C4           2                 8.0%                 3.1%                32.1%                56.8% S0-D0-C5           2                12.9%                 2.6%                37.8%                46.7% S0-D0-C6           2                16.1%                 2.7%                47.5%                33.6% S0-D0-C7           2                 9.8%                 1.3%                32.7%                56.1% S0-D0-C8           2                10.8%                 4.2%                48.0%                37.0% S0-D0-C9           2                 9.1%                 1.8%                30.9%                58.2%

跟可用pmutools看到更多细节：

# python3 ./toplev.py -l 2Will measure complete system.^C# 4.2-full-perf on Intel(R) Core(TM) i9-10900 CPU @ 2.80GHz [skl/skylake]C1    BE             Backend_Bound               % Slots                   89.2 C1    BE/Mem         Backend_Bound.Memory_Bound  % Slots                   49.2  <==  This metric represents fraction of slots the Memory  subsystem within the Backend was a bottleneck...C1    BE/Core        Backend_Bound.Core_Bound    % Slots                   39.9   This metric represents fraction of slots where Core non-  memory issues were of a bottleneck...C1-T0 MUX                                        %                         14.1   PerfMon Event Multiplexing accuracy indicatorC2    BE             Backend_Bound               % Slots                   89.1 C2    BE/Mem         Backend_Bound.Memory_Bound  % Slots                   49.1  <==C2    BE/Core        Backend_Bound.Core_Bound    % Slots                   40.0 C2-T0 MUX                                        %                         14.1 C1-T1 MUX                                        %                         14.2 C2-T1 MUX                                        %                         14.1 Run toplev --describe Memory_Bound^ to get more information on bottleneck for cpuAdd --nodes '!+Memory_Bound*/3,+MUX' for breakdown.Idle CPUs 0,3-10,13-19 may have been hidden. Override with --idle-threshold 100