I have been doing some image processing on my computer using .  Specifically, I am running a 5x5 median filter on imagery.  I can specify the number of processes that occur simultaneously within the Erdas batch command window.  I have been observing unusual behavior when I specify 16 simultaneous processes, which lead me to double check the number of processors on the machine.  I used the following command prompt command to assess the number of processors:  wmic cpu &gt; cpu.txt   Which yielded (in part):  Number of Cores: 8  Number of Logical Processors: 16   How does the number of cores differ from the number of logical processors in the context of software like Erdas imagine where the user can specify the number of simultaneous processes?  I am trying to determine if I should be specifying 8 or 16 simultaneous processes to maximize efficiency.
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I am confused by the difference between "Cores" and "Processors". A lot of the computers are 2-cores, 4-cores. Does this mean that they have one processor with 2 or 4 cores on that single processor?  Also, for intel core i5, it seems that there are 4 CPUs in the task manager, are they referring to 4 core on a processors, or 4 processors with one core each, or 2 cores on 2 processors?
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I wonder what's the difference between a dual core computer and a computer with 2 processors on the mother board.. I think it's something related with the threads but a I don't understand it very well..
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Why, for example, would a 2.66 GHz dual-core Core i5 be faster than a 2.66 GHz Core 2 Duo, which is also dual-core?  Is this because of newer instructions that can process information in fewer clock cycles? What other architectural changes are involved?     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this question. Feel free to edit the answers to add additional details.
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The CPU is a i7-3770@3.40GHz. It has 4 cores and each core has 2 threads. Here is the dmidecode output:  # dmidecode -t 4 # dmidecode 2.9 SMBIOS 2.7 present.  Handle 0x0042, DMI type 4, 42 bytes Processor Information     Socket Designation: SOCKET 0     Type: Central Processor     Family: &lt;OUT OF SPEC&gt;     Manufacturer: Intel(R) Corporation     ID: A9 06 03 00 FF FB EB BF     Version: Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz     Voltage: 1.1 V     External Clock: 100 MHz     Max Speed: 3800 MHz     Current Speed: 3400 MHz     Status: Populated, Enabled     Upgrade: &lt;OUT OF SPEC&gt;     L1 Cache Handle: 0x003F     L2 Cache Handle: 0x003E     L3 Cache Handle: 0x0040     Serial Number: Not Specified     Asset Tag: Fill By OEM     Part Number: Fill By OEM     Core Count: 4     Core Enabled: 4     Thread Count: 8     Characteristics:         64-bit capable   It will be 8 logic core in a system, like what shows in /proc/cpuinfo. But can any one tell why the cpu MHz of a core is 1600MHz? I guess there is 2 threads in a core, so a hw thread freq may be about the half of the core's? How this number is calculated?  processor   : 7 vendor_id   : GenuineIntel cpu family  : 6 model       : 58 model name  : Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz stepping    : 9 cpu MHz     : 1600.000 cache size  : 8192 KB physical id : 0 siblings    : 8 core id     : 3 cpu cores   : 4 apicid      : 7 initial apicid  : 7 fpu     : yes fpu_exception   : yes cpuid level : 13 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 rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 x2apic popcnt aes xsave avx lahf_lm ida arat tpr_shadow vnmi flexpriority ept vpid bogomips    : 7013.49 clflush size    : 64 cache_alignment : 64 address sizes   : 36 bits physical, 48 bits virtual power management:   Also, here is the output of lshw and lscpu command. There are also 1600MHz mentioned.   lshw info:  #lshw -class processor   *-cpu                           description: CPU        product: Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz        vendor: Intel Corp.        physical id: 42        bus info: cpu@0        version: Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz        slot: SOCKET 0        size: 1600MHz        capacity: 3800MHz        width: 64 bits        clock: 100MHz        capabilities: fpu fpu_exception wp 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 rdtscp x86-64 constant_tsc arch_perfmon pebs bts rep_good xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 x2apic popcnt aes xsave avx lahf_lm ida arat tpr_shadow vnmi flexpriority ept vpid cpufreq   lscpu info:  #lscpu Architecture:          x86_64 CPU op-mode(s):        32-bit, 64-bit CPU(s):                8 Thread(s) per core:    2 Core(s) per socket:    4 CPU socket(s):         1 NUMA node(s):          1 Vendor ID:             GenuineIntel CPU family:            6 Model:                 58 Stepping:              9 CPU MHz:               1600.000 Virtualization:        VT-x L1d cache:             32K L1i cache:             32K L2 cache:              256K L3 cache:              8192K
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How to limit process to one cpu core ?  Something similar to ulimit or cpulimit would be nice. (Just to ensure: I do NOT want to limit percentage usage or time of execution. I want to force app (with all it's children, processes (threads)) to use one cpu core (or 'n' cpu cores)).
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You can see the output from lscpu command -  jack@042:~$ lscpu Architecture:          x86_64 CPU op-mode(s):        32-bit, 64-bit Byte Order:            Little Endian CPU(s):                56 On-line CPU(s) list:   0-55 Thread(s) per core:    2 Core(s) per socket:    14 Socket(s):             2 NUMA node(s):          2 Vendor ID:             GenuineIntel CPU family:            6 Model:                 79 Model name:            Intel(R) Xeon(R) CPU E5-2690 v4 @ 2.60GHz Stepping:              1 CPU MHz:               2600.000 CPU max MHz:           2600.0000 CPU min MHz:           1200.0000 BogoMIPS:              5201.37 Virtualization:        VT-x Hypervisor vendor:     vertical Virtualization type:   full L1d cache:             32K L1i cache:             32K L2 cache:              256K L3 cache:              35840K NUMA node0 CPU(s):     0-13,28-41 NUMA node1 CPU(s):     14-27,42-55   I can see that there are 2 sockets (which is like a processor ??) and inside each of the socket we have 14 cores. So, in total 2x14=28 physical cores. Normally, a CPU can contain multiple cores, so number of CPUs can never be smaller than number of Cores. But, as shown in the output CPUs(s): 56 and this is what is confusing me.  I can see that Thread(s) per core:    2, so these 28 cores can behave like 2x28=56 logical cores.  Question 1: What does this CPUs(s): 56 denote? Does CPU(s) denote number of Virtual/Logical core, as it cannot be a Physical core core atleast?  Question 2: What does this NUMA node mean? Does it represent the socket?
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I am using Drupal multi-sites (single codebase, multiple sites/*). Along with this, I have started using Drush aliases to manage them:  $ cat sites/all/drush/aliases.drushrc.php &lt;?php $aliases['localdev'] = array(   'site-list' =&gt; array(     'site1',      'site2',     'site3',   ), ); ?&gt;   This allows me to easily perform actions on all sites:  $ drush @localdev cc all   >> I've also just discovered that I can just use , and forgo the drushrc file.  Doing this, will execute "cc all" on each of my sites in series (one at a time).  I'd like to take this to the next level and try to run these commands on all sites simulantiously. I've been doing some reading, and am under the impression that Drush   support this. The  takes $backend_options, which can contain (from function documentation):   *      'invoke-multiple'  *        If $site_alias_record represents a single site, then 'invoke-multiple'  *        will cause the _same_ command with the _same_ arguments and options  *        to be invoked concurrently (e.g. for running concurrent batch processes).  *      'concurrency'  *        Limits the number of concurrent processes that will run at the same time.  *        Defaults to '4'.   What I can't figure out, however, is how do I actually use this from the Drush command line. Is there an option I need to pass to Drush, or do I need to set something in a settings file?   Any info will be much appreciated - my curiosity is piqued!   UPDATE  Based on the answers below, I was able to create a simple test that demonstrates Drush's behaviour, and draw some conclusions:  Drush's default behaviour when executing operations on multiple sites is to use concurrent processes:  $ drush @localdev ev "drupal_set_message(time()); sleep(5);"  Continue?  (y/n): y site1             &gt;&gt; 1360512943      [status] site2             &gt;&gt; 1360512943      [status] site3             &gt;&gt; 1360512943      [status]   This is true even when not using aliases, and is also true when using Drush's built-in @sites alias. These two commands yield identical behaviour as above:  $ drush site1,site2,site3 ev "drupal_set_message(time()); sleep(5);" $ drush @sites ev "drupal_set_message(time()); sleep(5);"   To change the number of concurrent processes (default is 4), the '--concurrency=N' option can be passed in the drush command. For example, if I want serial execution, I can set the number of concurrent processes to 1:  $ drush @localdev ev "drupal_set_message(time()); sleep(5);" --concurrency=1  Continue?  (y/n): y site1             &gt;&gt; 1360513387      [status] site2             &gt;&gt; 1360513393      [status] site3             &gt;&gt; 1360513399      [status]
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Why are some processes in Windows 8 32-bit? For example: I have the 64 bit version of iTunes, but it is a 32 bit process(in Task Manager). Why is this so?
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According to  on MDN, Firefox 57 finally runs things in different processes.  So is Firefox 57 multithreaded?  In particular, how many cores does it use at most? Say I open 20 tabs at once on a quad-core machine, will Firefox 57 launch as many threads, or at least as many as needed to max out my CPU?  (Chromium for instance spawns a number of sub-processes and very easily uses all the resources available. Firefox up to 56 in GNU/Linux is rarely seen going over 135 % of one core however many tabs I open.)
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I recently installed 8GB of RAM onto a quad core workstation (HP xw8600) running Windows XP Pro (32-bit).  I added the /PAE switch in the boot.ini file, but the SysInfo is saying 3GB total memory still.  Is Windows recognizing the extra memory?  Is there a way to tell?  Any help is appreciated.  Thanks.
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I am using \write18 enabled (or --shell-escape) with externalization to compile a bunch of PGFplots. The first run takes much time, and I noticed that pdflatex only runs on one CPU core.  Is there any way to have pdflatex use multiple cores? (at least when \write18 is enabled)
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I am thinking of getting a dual Intel Xeon machine, each CPU is a quad core.  Will Ubuntu utilize both processors, especially with both being quad core, optimally?  Wanting to do Video editing and processing, but the Xeon machine's clock speed is actually slower than my current computer, so if both procs are not being used, I will actually end up with a slower machine than I already have.  I am not too familiar with dual processor machines. Thanks in advance for any answers.
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I've installed Process Lasso and in All processes tab, set all affinities to 1-7, meaning that all the processes can be start on all my CPUs except the first one. Yet, there is a huge load on my first CPU.   I personally have no clue what's happening here and really appreciate any help.  My system is:   Intel core i7 - 4720 HQ  2.6 GHz upto 3.6 Windows 10 (64 bit) NVidia GTX 950 M   This screenshot, shows the software's interface. Those 8 green bars on upper right show my CPU usage. Also the column called Rules, indicates the affinities on the processes.       PS: These are screenshots that show the more familiar Task Manager and Resource Monitor. I've sorted all with respect to their CPU usage. Note that the overall CPU usage is just fine (less than 30% most of the time), but in Resource Monitor, same as the Process Lasso, it's obvious that that most of the load is on CPU0 and the others are almost free.  Also I found out that my total CPU usage, is actually more than all my processes altogether! The orange line in Resource Monitor picture, shows the amount of CPU usage of all my processes. (I did the same in safe mode. Orange line, exactly coincides the total usage in safe mode. So I'm suspecting that something is happening in my normal boot.)
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I am on Ubuntu and I did this command:  $ uname -a Linux slabrams-desktop 2.6.32-29-generic #58-Ubuntu SMP Fri Feb 11 19:00:09 UTC 2011 i686 GNU/Linux   Does it mean I am on 32bit or 64 bit processor?  The reason I am trying to figure this out is that I was getting errors which looked like this:  cannot execute binary file   and from Googling, I thought it was a processor issue.  Any ideas?
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Environment:   Host OS: Win7 Pro 64bit Guest OS: WinXP 32bit VirtualBox version: 4.1.4r74291 Processor: Intel Core i7 2630QM with virtualization enabled   The Problem:  I need the guest system to use multiple cores. I have enabled the following options in VirtualBox:    IO APIC (motherboard tab) PAE/NX (processor tab) VT-x/AMD-V (acceleration) nested paging (acceleration)   All other options on the System submenu are switched of. The 'processors' slider is set to 8.  The problem is that the guest system runs correctly, but only one processor/core is visible.
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According to this  on Facebook's Haystack:     "Because of how the NAS appliances manage directory metadata, placing   thousands of ﬁles in a directory was extremely inefﬁcient as the   directory’s blockmap was too large to be cached effectively by the   appliance. Consequently it was common to incur more than 10 disk   operations to retrieve a single image. After reducing directory sizes   to hundreds of images per directory, the resulting system would still   generally incur 3 disk operations to fetch an image: one to read the   directory metadata into memory, a second to load the inode into   memory, and a third to read the ﬁle contents."   I had assumed the filesystem directory metadata &amp; inode would always be cached in RAM by the OS and a file read would usually require just 1 disk IO.   Is this "multiple disk IO's to read a single file" problem outlined in that paper unique to NAS appliances, or does Linux have the same problem too?  I'm planning to run a Linux server for serving images. Any way I can minimize the number of disk IO - ideally making sure the OS caches all the directory &amp; inode data in RAM and each file reads would only require no more than 1 disk IO?
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I have two servers running SQL Server.   Server 1: SQL Server 2008 R2 Express (4 core) Server 2: SQL Server 2012 Developer Edition (8 core)   As far as I am aware SQL Server 2008 R2 Express should only use one core.  SQL Server 2012 Developer version should use all 8 cores.  However if I run the following command inside of SQL query on SQL Server 2008 R2 Express it's showing 4 cores.  select scheduler_id, cpu_id, status, is_online  from sys.dm_os_schedulers  where status = 'VISIBLE ONLINE'   Am I using the right command to gauge the usage?