I notice a very high cpu usage when I do for example an (internet) speed test or download a file. Everything that causes a lot of write to the SSD causes almost maximum CPU usage on my notebook.

Hardware Info


Xubuntu 16.04.1 (installed only a week ago and updated today)

uname -a:

Linux xiaolong-hp-pavilion 4.4.0-62-generic #83-Ubuntu SMP Wed Jan 18 14:10:15 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

PCI Devices

Output of lspci:

00:00.0 Host bridge: Intel Corporation Device 5904 (rev 02)
00:02.0 VGA compatible controller: Intel Corporation Device 5916 (rev 02)
00:04.0 Signal processing controller: Intel Corporation Skylake Processor Thermal Subsystem (rev 02)
00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21)
00:14.2 Signal processing controller: Intel Corporation Sunrise Point-LP Thermal subsystem (rev 21)
00:16.0 Communication controller: Intel Corporation Sunrise Point-LP CSME HECI (rev 21)
00:17.0 SATA controller: Intel Corporation Sunrise Point-LP SATA Controller [AHCI mode] (rev 21)
00:1c.0 PCI bridge: Intel Corporation Device 9d10 (rev f1)
00:1c.4 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port (rev f1)
00:1c.5 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port (rev f1)
00:1d.0 PCI bridge: Intel Corporation Device 9d18 (rev f1)
00:1d.3 PCI bridge: Intel Corporation Device 9d1b (rev f1)
00:1f.0 ISA bridge: Intel Corporation Device 9d58 (rev 21)
00:1f.2 Memory controller: Intel Corporation Sunrise Point-LP PMC (rev 21)
00:1f.3 Audio device: Intel Corporation Device 9d71 (rev 21)
00:1f.4 SMBus: Intel Corporation Sunrise Point-LP SMBus (rev 21)
01:00.0 3D controller: NVIDIA Corporation GM108M [GeForce 940MX] (rev a2)
02:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS522A PCI Express Card Reader (rev 01)
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller (rev 0a)
05:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter

HDD Info

The output of sudo hdparm -I /dev/sda:


ATA device, with non-removable media
    Model Number:       SAMSUNG MZNTY256HDHP-000H1              
    Serial Number:      S2ZPNY0H905855      
    Firmware Revision:  MAT21H3Q
    Transport:          Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6, SATA Rev 3.0
    Used: unknown (minor revision code 0x0039) 
    Supported: 10 9 8 7 6 5 
    Likely used: 10
    Logical     max current
    cylinders   16383   0
    heads       16  0
    sectors/track   63  0
    LBA    user addressable sectors:  268435455
    LBA48  user addressable sectors:  500118192
    Logical  Sector size:                   512 bytes
    Physical Sector size:                  4096 bytes
    Logical Sector-0 offset:                  0 bytes
    device size with M = 1024*1024:      244198 MBytes
    device size with M = 1000*1000:      256060 MBytes (256 GB)
    cache/buffer size  = unknown
    Form Factor: less than 1.8 inch
    Nominal Media Rotation Rate: Solid State Device
    LBA, IORDY(can be disabled)
    Queue depth: 32
    Standby timer values: spec'd by Standard, no device specific minimum
    R/W multiple sector transfer: Max = 16  Current = 16
    Advanced power management level: 254
    DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5 
         Cycle time: min=120ns recommended=120ns
    PIO: pio0 pio1 pio2 pio3 pio4 
         Cycle time: no flow control=120ns  IORDY flow control=120ns
    Enabled Supported:
       *    SMART feature set
            Security Mode feature set
       *    Power Management feature set
       *    Write cache
       *    Look-ahead
       *    WRITE_BUFFER command
       *    READ_BUFFER command
       *    NOP cmd
       *    Advanced Power Management feature set
       *    48-bit Address feature set
       *    Mandatory FLUSH_CACHE
       *    FLUSH_CACHE_EXT
       *    SMART error logging
       *    SMART self-test
       *    General Purpose Logging feature set
       *    64-bit World wide name
       *    IDLE_IMMEDIATE with UNLOAD
       *    WRITE_UNCORRECTABLE_EXT command
       *    {READ,WRITE}_DMA_EXT_GPL commands
       *    Segmented DOWNLOAD_MICROCODE
            unknown 119[6]
            unknown 119[8]
            unknown 119[9]
       *    Gen1 signaling speed (1.5Gb/s)
       *    Gen2 signaling speed (3.0Gb/s)
       *    Gen3 signaling speed (6.0Gb/s)
       *    Native Command Queueing (NCQ)
       *    Phy event counters
       *    READ_LOG_DMA_EXT equivalent to READ_LOG_EXT
       *    DMA Setup Auto-Activate optimization
            Device-initiated interface power management
            Asynchronous notification (eg. media change)
       *    Software settings preservation
            unknown 78[7]
            Device Sleep (DEVSLP)
       *    SMART Command Transport (SCT) feature set
       *    SCT Write Same (AC2)
       *    SCT Error Recovery Control (AC3)
       *    SCT Features Control (AC4)
       *    SCT Data Tables (AC5)
       *    reserved 69[3]
       *    DOWNLOAD MICROCODE DMA command
       *    WRITE BUFFER DMA command
       *    READ BUFFER DMA command
       *    Data Set Management TRIM supported (limit 8 blocks)
       *    Deterministic read ZEROs after TRIM
    Master password revision code = 65534
    not enabled
    not locked
    not frozen
    not expired: security count
        supported: enhanced erase
Logical Unit WWN Device Identifier: 5002538d001d6d69
    NAA     : 5
    IEEE OUI    : 002538
    Unique ID   : d001d6d69
Device Sleep:
    DEVSLP Exit Timeout (DETO): 50 ms (drive)
    Minimum DEVSLP Assertion Time (MDAT): 30 ms (drive)
Checksum: correct

File System

Output of stat -f -c %T /:


What could be the reason and what can I do about this?

1 Answer 1


I don't know exactly what was going on, but I found a solution:

I had to add pcie_aspm=off to the line


resulting in:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splashi pcie_aspm=off"

After that and installing the Nvidia graphics card driver from downloaded driver file after stopping lightdm, the problem went away.

I am not sure if the Nvidia driver had anything to do with it, but the pcie parameter also fixed high CPU usage of systemd-journald, which was logging pcie errors on physical layer all the time.

However, I read elsewhere, that this parameter disables some power saving measures. Probably the ones for PCIe devices, which is unfortunate.

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