CPU 사용량이 60~70%를 넘지 않는 이유는 무엇입니까? 병목 현상은 어디에 있습니까?

최근 내 CPU 그래프에서 컴파일할 때 사용량이 100%에 도달하지 못하는 것 같고 최대 60~70% 정도 위아래로 변동한다는 사실을 발견했습니다.

예:

대조적으로, 업무용 컴퓨터에서 작업을 수행하면 플롯이 완전히 불투명해집니다.

나는 이것을 알아 내려고 노력하고 있습니다.압력CPU 사용량을 시뮬레이션하는 유틸리티와 관찰할 vmstat입니다. 내 CPU 코어 수는 1~15개(내 CPU에는 12개의 논리 코어가 있음)이며 실행 스트레스가 높습니다. 결과는 다음과 같습니다. 행 1은 100% 실행 중인 코어 1개에 해당하고, 행 2는 코어 2개에 해당합니다.

procs -----------------------memory---------------------- ---swap-- -----io---- -system-- --------cpu--------
r  b         swpd         free         buff        cache   si   so    bi    bo   in   cs  us  sy  id  wa  st
1  0            0     24455180       465548      2862716    0    0     0    38  944 3184  11   1  88   0   0
3  0            0     24508640       465552      2862684    0    0     0   196 1112 2841  18   1  81   0   0
3  0            0     24556876       465564      2865096    0    0     0    63 1880 4569  30   1  70   0   0
4  0            0     24624764       465576      2865044    0    0     0    11 1414 1005  34   0  66   0   0
5  0            0     24625228       465580      2865068    0    0     0     9 1603 1029  42   0  58   0   0
6  0            0     24763772       465600      2864912    0    0     1   159 1973 1032  51   0  49   0   0
8  0            0     24786696       465600      2864844    0    0     0     9 2460  751  56   0  44   0   0
8  0            0     24805572       465600      2864864    0    0     0    78 2619  808  61   0  38   0   0
10  0            0     24811064       465604      2864852    0    0     0    50 2532  761  56   0  44   0   0
14  0            0     24809904       465616      2865180    0    0     0     4 2823 1049  63   0  37   0   0
13  0            0     24868936       465620      2865116    0    0     0    76 2596  709  57   0  43   0   0
19  0            0     24910408       465628      2866136    0    0     0    12 2526  738  56   0  44   0   0
16  0            0     24914768       465636      2865244    0    0     0    36 2757  720  62   0  38   0   0
18  0            0     24914332       465644      2865256    0    0     0     3 2629  862  59   0  41   0   0
19  0            0     24945952       465648      2866224    0    0     0    33 2642  678  59   0  41   0   0

내가 실행하는 스크립트:

for corecount in $(seq 15); do
    stress -c $corecount >/dev/null&
    sleep 1
    vmstat -w 4 2 | tail -1
    pkill stress
    sleep 1
done

열 을 보면 usCPU 사용량이 최대 6~8개의 논리 코어까지 예상대로 선형적으로 증가하지만 다른 병목 현상이 발생하는 것을 볼 수 있습니다. 이 시점에서 마우스 커서가 지연되기 시작하고 비디오 플레이어가 실행되는 동안 마우스 커서를 실행하려고 하면 이 시점에서 더듬거리기 시작합니다. (비교를 위해 내 업무용 컴퓨터에서 정확히 동일한 테스트를 수행했습니다.http://pastebin.com/MHPSR4E0. 여기서 CPU 사용량은 선형적으로 99/100까지 올라가고 그대로 유지됩니다(포화도는 8코어 CPU이므로 8라인에 있습니다).

(이것은 전체 테스트 실행에 대한 CPU 그래프이며, 초크 포인트가 표시됩니다 . :)

일반 정보:

Ubuntu 16.04 LTS, 32GB RAM, i7-5820K 6코어 CPU.

무료-h

              total        used        free      shared  buff/cache   available
Mem:            31G        4,8G         23G         90M        3,3G         26G
Swap:           15G          0B         15G

/proc/cpu 정보

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 63
model name      : Intel(R) Core(TM) i7-5820K CPU @ 3.30GHz
stepping        : 2
microcode       : 0x2d
cpu MHz         : 1236.339
cache size      : 15360 KB
physical id     : 0
siblings        : 12
core id         : 0
cpu cores       : 6
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 15
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm ida arat pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid cqm xsaveopt cqm_llc cqm_occup_llc
bugs            :
bogomips        : 6599.39
clflush size    : 64
cache_alignment : 64
address sizes   : 46 bits physical, 48 bits virtual
power management:

[...]

processor       : 11
vendor_id       : GenuineIntel
cpu family      : 6
model           : 63
model name      : Intel(R) Core(TM) i7-5820K CPU @ 3.30GHz
stepping        : 2
microcode       : 0x2d
cpu MHz         : 1200.246
cache size      : 15360 KB
physical id     : 0
siblings        : 12
core id         : 5
cpu cores       : 6
apicid          : 11
initial apicid  : 11
fpu             : yes
fpu_exception   : yes
cpuid level     : 15
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm ida arat pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid cqm xsaveopt cqm_llc cqm_occup_llc
bugs            :
bogomips        : 6599.39
clflush size    : 64
cache_alignment : 64
address sizes   : 46 bits physical, 48 bits virtual
power management:

lspci

00:00.0 Host bridge: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DMI2 (rev 02)
00:01.0 PCI bridge: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 PCI Express Root Port 1 (rev 02)
00:01.1 PCI bridge: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 PCI Express Root Port 1 (rev 02)
00:02.0 PCI bridge: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 PCI Express Root Port 2 (rev 02)
00:02.2 PCI bridge: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 PCI Express Root Port 2 (rev 02)
00:02.3 PCI bridge: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 PCI Express Root Port 2 (rev 02)
00:03.0 PCI bridge: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 PCI Express Root Port 3 (rev 02)
00:05.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Address Map, VTd_Misc, System Management (rev 02)
00:05.1 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Hot Plug (rev 02)
00:05.2 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 RAS, Control Status and Global Errors (rev 02)
00:05.4 PIC: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 I/O APIC (rev 02)
00:11.0 Unassigned class [ff00]: Intel Corporation C610/X99 series chipset SPSR (rev 05)
00:14.0 USB controller: Intel Corporation C610/X99 series chipset USB xHCI Host Controller (rev 05)
00:16.0 Communication controller: Intel Corporation C610/X99 series chipset MEI Controller #1 (rev 05)
00:19.0 Ethernet controller: Intel Corporation Ethernet Connection (2) I218-V (rev 05)
00:1a.0 USB controller: Intel Corporation C610/X99 series chipset USB Enhanced Host Controller #2 (rev 05)
00:1b.0 Audio device: Intel Corporation C610/X99 series chipset HD Audio Controller (rev 05)
00:1c.0 PCI bridge: Intel Corporation C610/X99 series chipset PCI Express Root Port #1 (rev d5)
00:1c.4 PCI bridge: Intel Corporation C610/X99 series chipset PCI Express Root Port #5 (rev d5)
00:1d.0 USB controller: Intel Corporation C610/X99 series chipset USB Enhanced Host Controller #1 (rev 05)
00:1f.0 ISA bridge: Intel Corporation C610/X99 series chipset LPC Controller (rev 05)
00:1f.2 SATA controller: Intel Corporation C610/X99 series chipset 6-Port SATA Controller [AHCI mode] (rev 05)
00:1f.3 SMBus: Intel Corporation C610/X99 series chipset SMBus Controller (rev 05)
06:00.0 VGA compatible controller: NVIDIA Corporation GF104 [GeForce GTX 460] (rev a1)
06:00.1 Audio device: NVIDIA Corporation GF104 High Definition Audio Controller (rev a1)
08:00.0 USB controller: ASMedia Technology Inc. ASM1142 USB 3.1 Host Controller
ff:0b.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 R3 QPI Link 0 & 1 Monitoring (rev 02)
ff:0b.1 Performance counters: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 R3 QPI Link 0 & 1 Monitoring (rev 02)
ff:0b.2 Performance counters: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 R3 QPI Link 0 & 1 Monitoring (rev 02)
ff:0c.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Unicast Registers (rev 02)
ff:0c.1 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Unicast Registers (rev 02)
ff:0c.2 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Unicast Registers (rev 02)
ff:0c.3 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Unicast Registers (rev 02)
ff:0c.4 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Unicast Registers (rev 02)
ff:0c.5 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Unicast Registers (rev 02)
ff:0f.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Buffered Ring Agent (rev 02)
ff:0f.1 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Buffered Ring Agent (rev 02)
ff:0f.4 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 System Address Decoder & Broadcast Registers (rev 02)
ff:0f.5 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 System Address Decoder & Broadcast Registers (rev 02)
ff:0f.6 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 System Address Decoder & Broadcast Registers (rev 02)
ff:10.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 PCIe Ring Interface (rev 02)
ff:10.1 Performance counters: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 PCIe Ring Interface (rev 02)
ff:10.5 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 02)
ff:10.6 Performance counters: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 02)
ff:10.7 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 02)
ff:12.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Home Agent 0 (rev 02)
ff:12.1 Performance counters: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Home Agent 0 (rev 02)
ff:13.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Target Address, Thermal & RAS Registers (rev 02)
ff:13.1 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Target Address, Thermal & RAS Registers (rev 02)
ff:13.2 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel Target Address Decoder (rev 02)
ff:13.3 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel Target Address Decoder (rev 02)
ff:13.4 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel Target Address Decoder (rev 02)
ff:13.5 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel Target Address Decoder (rev 02)
ff:13.6 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DDRIO Channel 0/1 Broadcast (rev 02)
ff:13.7 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DDRIO Global Broadcast (rev 02)
ff:14.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel 0 Thermal Control (rev 02)
ff:14.1 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel 1 Thermal Control (rev 02)
ff:14.2 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel 0 ERROR Registers (rev 02)
ff:14.3 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel 1 ERROR Registers (rev 02)
ff:14.6 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DDRIO (VMSE) 0 & 1 (rev 02)
ff:14.7 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DDRIO (VMSE) 0 & 1 (rev 02)
ff:15.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel 2 Thermal Control (rev 02)
ff:15.1 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel 3 Thermal Control (rev 02)
ff:15.2 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel 2 ERROR Registers (rev 02)
ff:15.3 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 0 Channel 3 ERROR Registers (rev 02)
ff:16.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 1 Target Address, Thermal & RAS Registers (rev 02)
ff:16.6 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DDRIO Channel 2/3 Broadcast (rev 02)
ff:16.7 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DDRIO Global Broadcast (rev 02)
ff:17.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Integrated Memory Controller 1 Channel 0 Thermal Control (rev 02)
ff:17.4 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DDRIO (VMSE) 2 & 3 (rev 02)
ff:17.5 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DDRIO (VMSE) 2 & 3 (rev 02)
ff:17.6 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DDRIO (VMSE) 2 & 3 (rev 02)
ff:17.7 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DDRIO (VMSE) 2 & 3 (rev 02)
ff:1e.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Power Control Unit (rev 02)
ff:1e.1 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Power Control Unit (rev 02)
ff:1e.2 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Power Control Unit (rev 02)
ff:1e.3 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Power Control Unit (rev 02)
ff:1e.4 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 Power Control Unit (rev 02)
ff:1f.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 VCU (rev 02)
ff:1f.2 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 VCU (rev 02)

/proc/메모리 정보

MemTotal:       32841924 kB
MemFree:        24244428 kB
MemAvailable:   27418672 kB
Buffers:          478012 kB
Cached:          2622028 kB
SwapCached:            0 kB
Active:          6606180 kB
Inactive:        1240728 kB
Active(anon):    4758584 kB
Inactive(anon):    85340 kB
Active(file):    1847596 kB
Inactive(file):  1155388 kB
Unevictable:        8020 kB
Mlocked:            8020 kB
SwapTotal:      16669692 kB
SwapFree:       16669692 kB
Dirty:               284 kB
Writeback:             0 kB
AnonPages:       4754864 kB
Mapped:           780304 kB
Shmem:             93528 kB
Slab:             346300 kB
SReclaimable:     257036 kB
SUnreclaim:        89264 kB
KernelStack:       22112 kB
PageTables:       109808 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:    33090652 kB
Committed_AS:   16302224 kB
VmallocTotal:   34359738367 kB
VmallocUsed:      371016 kB
VmallocChunk:   34358945788 kB
HardwareCorrupted:     0 kB
AnonHugePages:    761856 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:      537784 kB
DirectMap2M:     5648384 kB
DirectMap1G:    29360128 kB

10개 코어를 사용한 스트레스 테스트 중 ksysguard의 CPU 사용량에 대한 자세한 스크린샷:

무슨 일이야?무슨 일이 일어나고 있는지 이해하기 위해 커널의 다른 어떤 부분을 관찰할 수 있나요? CPU 스케줄러 구성이 있습니까? 항상 그런 것은 아닙니다. 이전에는 마우스 지연 없이 100% CPU 활용률로 컴파일할 수 있었고 팬이 작동하는 것 외에는 실제로 눈치채지 못했을 것이라고 확신합니다.