我在配备 i7-4710HQ 处理器的华硕笔记本电脑上运行 Ubuntu。我对 cpu-freq 缩放有些问题。当我使用 intel-pstate 驱动程序时，频率总是很高（2.5GHz 时为 90%）。我读过帖子空闲时 CPU 频率高并更改内核行参数以禁用 intel-pstate 驱动程序，并且 CPU 频率缩放工作正常，但系统即使在 AC 上也不使用 turbo 模式 (3.5GHz)。
intel-pstate驱动程序可以正常工作吗？
下面是我使用 cpufreq_histogram 进行的一些测试。
全新启动，无需启动任何附加程序。
old cpufreq driver:
sudo ./cpufreq_histogram.sh 300
Collecting data for 300 seconds...
# NumSamples = 300; Min = 800.00; Max = 2100.00
# Mean = 856.000000; Variance = 36864.000000; SD = 192.000000; Median 800.000000
# each ∎ represents a count of 3
800.0000 - 930.0000 [ 284]: ∎∎∎∎∎ ... ∎∎∎∎∎ (94.67%)
930.0000 - 1060.0000 [ 2]: (0.67%)
1060.0000 - 1190.0000 [ 0]: (0.00%)
1190.0000 - 1320.0000 [ 3]: ∎ (1.00%)
1320.0000 - 1450.0000 [ 1]: (0.33%)
1450.0000 - 1580.0000 [ 1]: (0.33%)
1580.0000 - 1710.0000 [ 1]: (0.33%)
1710.0000 - 1840.0000 [ 5]: ∎ (1.67%)
1840.0000 - 1970.0000 [ 1]: (0.33%)
1970.0000 - 2100.0000 [ 2]: (0.67%)
intel_pstate driver:
sudo ./cpufreq_histogram.sh 300
[sudo] hasło użytkownika mariusz:
Collecting data for 300 seconds...
# NumSamples = 300; Min = 868.90; Max = 3500.30
# Mean = 2062.607000; Variance = 536898.224651; SD = 732.733393; Median 1789.700000
# each ∎ represents a count of 1
868.9000 - 1132.0400 [ 14]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎ (4.67%)
1132.0400 - 1395.1800 [ 30]: ∎∎∎∎∎ ... ∎∎∎∎∎ (10.00%)
1395.1800 - 1658.3200 [ 84]: ∎∎∎∎∎ ... ∎∎∎∎∎ (28.00%)
1658.3200 - 1921.4600 [ 41]: ∎∎∎∎∎ ... ∎∎∎∎∎ (13.67%)
1921.4600 - 2184.6000 [ 16]: ∎∎∎∎∎ ... ∎∎∎∎∎ (5.33%)
2184.6000 - 2447.7400 [ 20]: ∎∎∎∎∎ ... ∎∎∎∎∎ (6.67%)
2447.7400 - 2710.8800 [ 38]: ∎∎∎∎∎ ... ∎∎∎∎∎ (12.67%)
2710.8800 - 2974.0200 [ 6]: ∎∎∎∎∎∎ (2.00%)
2974.0200 - 3237.1600 [ 8]: ∎∎∎∎∎∎∎∎ (2.67%)
3237.1600 - 3500.3000 [ 43]: ∎∎∎∎∎ ... ∎∎∎∎∎ (14.33%)
全新开始 - 带有 html5 视频解码的 chromium 浏览器。
Old cpufreq driver:
sudo ./cpufreq_histogram.sh 300
Collecting data for 300 seconds...
# NumSamples = 300; Min = 800.00; Max = 2300.00
# Mean = 974.666667; Variance = 44691.555556; SD = 211.403774; Median 900.000000
# each ∎ represents a count of 2
800.0000 - 950.0000 [ 182]: ∎∎∎∎∎ ... ∎∎∎∎∎ (60.67%)
950.0000 - 1100.0000 [ 71]: ∎∎∎∎∎ ... ∎∎∎∎∎ (23.67%)
1100.0000 - 1250.0000 [ 28]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎ (9.33%)
1250.0000 - 1400.0000 [ 9]: ∎∎∎∎ (3.00%)
1400.0000 - 1550.0000 [ 0]: (0.00%)
1550.0000 - 1700.0000 [ 2]: ∎ (0.67%)
1700.0000 - 1850.0000 [ 4]: ∎∎ (1.33%)
1850.0000 - 2000.0000 [ 3]: ∎ (1.00%)
2000.0000 - 2150.0000 [ 0]: (0.00%)
2150.0000 - 2300.0000 [ 1]: (0.33%)
intel_pstate driver:
sudo ./cpufreq_histogram.sh 300
Collecting data for 300 seconds...
# NumSamples = 300; Min = 800.00; Max = 3146.60
# Mean = 1847.854333; Variance = 230391.093281; SD = 479.990722; Median 1787.150000
# each ∎ represents a count of 1
800.0000 - 1034.6600 [ 13]: ∎∎∎∎∎∎∎∎∎∎∎∎∎ (4.33%)
1034.6600 - 1269.3200 [ 25]: ∎∎∎∎∎ ... ∎∎∎∎∎ (8.33%)
1269.3200 - 1503.9800 [ 33]: ∎∎∎∎∎ ... ∎∎∎∎∎ (11.00%)
1503.9800 - 1738.6400 [ 73]: ∎∎∎∎∎ ... ∎∎∎∎∎ (24.33%)
1738.6400 - 1973.3000 [ 42]: ∎∎∎∎∎ ... ∎∎∎∎∎ (14.00%)
1973.3000 - 2207.9600 [ 31]: ∎∎∎∎∎ ... ∎∎∎∎∎ (10.33%)
2207.9600 - 2442.6200 [ 32]: ∎∎∎∎∎ ... ∎∎∎∎∎ (10.67%)
2442.6200 - 2677.2800 [ 46]: ∎∎∎∎∎ ... ∎∎∎∎∎ (15.33%)
2677.2800 - 2911.9400 [ 2]: ∎∎ (0.67%)
2911.9400 - 3146.6000 [ 3]: ∎∎∎ (1.00%)
答案1
最后我找到了解决办法。
intel_pstate 驱动程序在某些 Intel Hswell 及更高版本的处理器上存在一些问题。Arch Linux 用户注意到这是 intel_pstate 和内核内部计时器的问题。当计时器设置为 300Hz（arch 中的默认值）时，intel_pstate 驱动程序过于敏感。在 Ubuntu 中，通用内核中的计时器设置为 250Hz。
当我测试 linux-lowlatency 内核（将 CONFIG_HZ 设置为 1000）时，问题似乎消失了（似乎，因为我已经在 4.11 lowlatency 内核中测试过，解决方案并没有解决这个问题）。chrome html5video 解码的电池寿命从 2.5 小时增加到 4.5 小时。下面是我使用 lowlatency 4.10.0 内核进行的测试。
Collecting data for 62 seconds...
# NumSamples = 62; Min = 799.80; Max = 3325.80
# Mean = 1332.198387; Variance = 413667.275965; SD = 643.169710; Median 1091.200000
# each ∎ represents a count of 1
799.8000 - 1052.4000 [ 29]: ∎∎∎∎∎∎∎...∎∎∎∎∎∎∎ (46.77%)
1052.4000 - 1305.0000 [ 14]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎ (22.58%)
1305.0000 - 1557.6000 [ 3]: ∎∎∎ (4.84%)
1557.6000 - 1810.2000 [ 5]: ∎∎∎∎∎ (8.06%)
1810.2000 - 2062.8000 [ 3]: ∎∎∎ (4.84%)
2062.8000 - 2315.4000 [ 0]: (0.00%)
2315.4000 - 2568.0000 [ 5]: ∎∎∎∎∎ (8.06%)
2568.0000 - 2820.6000 [ 0]: (0.00%)
2820.6000 - 3073.2000 [ 0]: (0.00%)
3073.2000 - 3325.8000 [ 3]: ∎∎∎ (4.84%)