Matlab R2013a spend nearly 100% in one of four CPUs, how to fix it?

When I debug an *.m file (about 300.0 kb) with several breakpoints, about 1.1 GB memory will be used.

And what's comfused me is the high CPU usage, nearly 100% for one of the four CPUs.

I tried several times but cannot fix it.

Ask for help. Thanks!

The following are the System information, CPUinfo, memory information, and Matlab version.

---------------------------- system information -------------------------

#uname -a
Linux She 2.6.32-573.el6.x86_64 #1 SMP Thu Jul 23 15:44:03 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

---------------------------- CPUinfo -------------------------

# dmidecode | grep -A81 'Processor Information'
Processor Information
  Socket Designation: CPU 1
  Type: Central Processor
  Family: Core i5
  Manufacturer: Intel            
  ID: A7 06 02 00 FF FB EB BF
  Signature: Type 0, Family 6, Model 42, Stepping 7
  Flags:
    FPU (Floating-point unit on-chip)
    VME (Virtual mode extension)
    DE (Debugging extension)
    PSE (Page size extension)
    TSC (Time stamp counter)
    MSR (Model specific registers)
    PAE (Physical address extension)
    MCE (Machine check exception)
    CX8 (CMPXCHG8 instruction supported)
    APIC (On-chip APIC hardware supported)
    SEP (Fast system call)
    MTRR (Memory type range registers)
    PGE (Page global enable)
    MCA (Machine check architecture)
    CMOV (Conditional move instruction supported)
    PAT (Page attribute table)
    PSE-36 (36-bit page size extension)
    CLFSH (CLFLUSH instruction supported)
    DS (Debug store)
    ACPI (ACPI supported)
    MMX (MMX technology supported)
    FXSR (FXSAVE and FXSTOR instructions supported)
    SSE (Streaming SIMD extensions)
    SSE2 (Streaming SIMD extensions 2)
    SS (Self-snoop)
    HTT (Multi-threading)
    TM (Thermal monitor supported)
    PBE (Pending break enabled)
  Version: Intel(R) Core(TM) i5-2400 CPU @ 3.10GH         
  Voltage: 0.0 V
  External Clock: 100 MHz
  Max Speed: 4000 MHz
  Current Speed: 3100 MHz
  Status: Populated, Enabled
  Upgrade: Other
  L1 Cache Handle: 0x0005
  L2 Cache Handle: 0x0006
  L3 Cache Handle: 0x0007
  Serial Number: Not Specified
  Asset Tag: Not Specified
  Part Number: Not Specified
  Core Count: 4
  Core Enabled: 4
  Thread Count: 4
  Characteristics:
    64-bit capable

Handle 0x0005, DMI type 7, 19 bytes
Cache Information
  Socket Designation: L1-Cache
  Configuration: Enabled, Not Socketed, Level 1
  Operational Mode: Write Back
  Location: Internal
  Installed Size: 256 kB
  Maximum Size: 256 kB
  Supported SRAM Types:
    Other
  Installed SRAM Type: Other
  Speed: Unknown
  Error Correction Type: None
  System Type: Unified
  Associativity: 8-way Set-associative

Handle 0x0006, DMI type 7, 19 bytes
Cache Information
  Socket Designation: L2-Cache
  Configuration: Enabled, Not Socketed, Level 2
  Operational Mode: Varies With Memory Address
  Location: Internal
  Installed Size: 1024 kB
  Maximum Size: 1024 kB
  Supported SRAM Types:
    Other
  Installed SRAM Type: Other

---------------------------- Memory information -------------------------

# dmidecode | grep -A16 "Memory Device$"
Memory Device
  Array Handle: 0x002E
  Error Information Handle: Not Provided
  Total Width: 64 bits
  Data Width: 64 bits
  Size: 8192 MB
  Form Factor: DIMM
  Set: None
  Locator: ChannelA-DIMM0
  Bank Locator: BANK 0
  Type: DDR3
  Type Detail: Synchronous
  Speed: 1333 MHz
  Manufacturer: Kingston
  Serial Number: 8F2814C8
  Asset Tag: 9876543210
  Part Number: 99U5471-052.A00LF 
--
Memory Device
  Array Handle: 0x002E
  Error Information Handle: Not Provided
  Total Width: 64 bits
  Data Width: 64 bits
  Size: 8192 MB
  Form Factor: DIMM
  Set: None
  Locator: ChannelB-DIMM0
  Bank Locator: BANK 2
  Type: DDR3
  Type Detail: Synchronous
  Speed: 1333 MHz
  Manufacturer: Kingston
  Serial Number: 0B169D83
  Asset Tag: 9876543210
  Part Number: 99U5471-038.A00LF 

---------------------------- Matlab version -------------------------

    >> ver
    -------------------------------------------------------------------------------------------------------
    MATLAB Version: 8.1.0.604 (R2013a)
    MATLAB License Number: xxxxxx
    Operating System: Linux 2.6.32-573.el6.x86_64 #1 SMP Thu Jul 23 15:44:03 UTC 2015 x86_64
    Java Version: Java 1.6.0_17-b04 with Sun Microsystems Inc. Java HotSpot(TM) 64-Bit Server VM mixed mode
    -------------------------------------------------------------------------------------------------------

[Walter Roberson]

Sorry, could you clarify the circumstances under which the CPU load acts like that?

[She]

Is this what you need? I'm not very clear about your request. The problem begins just at some breakpoint, what I did was just stop running and make small modification about the source code. Then matlab program failed to response, cpu cost turned to rise up to 100% and will keep until I kill it from the task manager.

The picture is the screenshot just several seconds after I stop the program and add a few characters into the source code.

I guess the only reason is the size of my *.m file, about 332.4 KB, the largest one I have ever written which is generated from all my functions.

Independent small function files can run well without such a confused problem.

[She]

Now, you see, several minutes passed, 100% cpu usage remains. Matlab is out of response.

[Walter Roberson]

Have you tried turning off automatic error analysis? In Preferences -> Code Analyzer, turn off "Enable integrated warning and error messages"

[She]

Thank you for your advice. I tried with option ' automatic error analysis' turning off, it can survive longer than before. But still cannot work out the broken problem, the program died again, also with 100% CPU usage.

[Adam]

You haven't shown any code. You would get that effect if you program a computationally intensive infinite loop so without seeing your code it is hard to suggest why it would

[She]

Thank you!

In fact, the program is stopped at some breakpoints, without the influence of any potential infinite loop. The problem occurred when I tried to write some words info the *.m file.

Now, I solved this bug with Emacs calling matlab-shell mode which is some more complicated than Matlab itself, but I can freely edit and debug it, that's valuable.

Another optional way is, open Matlab with '-singleCompThread' option, it works well , also promise free edit and debug.

Thanks all!