title: How to calculate -jN argument for GNU make and how it affect my android build?
body: <p>GNU make can handle parallel tasks with a -jN argument, and it's common to use a number of tasks N that's between 1 and 2 times the number of hardware threads on the computer being used for the build.</p>
  
  <p>E.g. on a dual-E5520 machine (2 CPUs, 4 cores per CPU, 2 threads per core), the fastest builds are made with commands between make -j16 and make -j32.</p>
  
  <p>Right now i dont know much about my build server but 
  when i run <code>cat /proc/cpuinfo</code></p>
  
  <p>it shows it has 4 processor 
  and each info is like this</p>
  
  <pre><code>processor   : 0
  vendor_id   : GenuineIntel
  cpu family  : 6
  model       : 37
  model name  : Intel(R) Core(TM) i3 CPU         530  @ 2.93GHz
  stepping    : 2
  cpu MHz     : 2933.000
  cache size  : 4096 KB
  physical id : 0
  siblings    : 4
  core id     : 0
  cpu cores   : 2
  apicid      : 0
  initial apicid  : 0
  fpu     : yes
  fpu_exception   : yes
  cpuid level : 11
  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 dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm arat tpr_shadow vnmi flexpriority ept vpid
  bogomips    : 5851.87
  clflush size    : 64
  cache_alignment : 64
  address sizes   : 36 bits physical, 48 bits virtual
  power management:
  </code></pre>
  
  <p><strong>Question:</strong></p>
  
  <p>1>so here how can i calculate N for my build?</p>
  
  <p>2>what if my system can support maximum 8 threads and if i give <code>make -j32</code>?</p>
  
  <p>3>what if i just use make then only 1 thread will be run for compilation? </p>