RFR: os::processor_id() for Mac OS X

[Gerard Ziemski]

Ping,

Do we need https://bugs.openjdk.java.net/browse/JDK-8199415 “Implement os::processor_id() on Mac OS X” ?


cheers

> On Jan 17, 2018, at 11:01 AM, Gerard Ziemski <gerard.ziemski at oracle.com> wrote:
> 
> hi all,
> 
> Please review this simple feature adding os::processor_id() implementation for Mac OS X:
> 
> http://cr.openjdk.java.net/~gziemski/zgc_os_processor_id/webrev/src/hotspot/os/bsd/os_bsd.cpp.udiff.html <http://cr.openjdk.java.net/~gziemski/zgc_os_processor_id/webrev/src/hotspot/os/bsd/os_bsd.cpp.udiff.html>
> 
> Here is a standalone test using such implementation:
> 
> #include <stdio.h>
> #include <unistd.h>
> #include <cpuid.h>
> #include <pthread.h>
> 
> int get_cpu_id() {
>  uint32_t EAX = 0; // must be set to 0
>  uint32_t EBX = 0;
>  uint32_t ECX = 0;
>  uint32_t EDX = 0;
>  __cpuid(1, EAX, EBX, ECX, EDX);
>  // Check EDX for Advanced Programmable Interrupt Controller
>  if ((EDX & bit_APIC) != 0) {
>    // EBX[bits 31:24] Local APIC ID: The initial APIC-ID is used to identify the executing logical processor.
>    return (EBX >> 24) & 0xFF;
>  }
>  return 0;
> }
> 
> void *tick(void *void_ptr)
> {
>  int thread_id = *((int *)void_ptr);
>  for (int i=0; i<10; i++) {
>    printf("thread: %2d running on cpu: %d\n", thread_id, get_cpu_id());
>    sleep(1);
>  }
>  return NULL;
> }
> 
> int main(int argc, const char * argv[]) {
>  int count = 32;
>  pthread_t thread[count];
>  for (int i=0; i<count; i++) {
>    pthread_create(&thread[i], NULL, tick, &i);
>  }
>  for (int i=0; i<count; i++) {
>    pthread_join(thread[i], NULL);
>  }
>  return 0;
> }
> 
> -------------------------------------------
> Outputs:
> 
> thread:  2 running on cpu: 4
> thread:  3 running on cpu: 5
> thread:  4 running on cpu: 2
> thread:  6 running on cpu: 1
> thread:  6 running on cpu: 5
> thread:  7 running on cpu: 1
> thread:  8 running on cpu: 7
> thread:  9 running on cpu: 5
> thread:  9 running on cpu: 7
> thread: 10 running on cpu: 3
> thread: 11 running on cpu: 3
> thread: 12 running on cpu: 2
> thread: 13 running on cpu: 3
> thread: 15 running on cpu: 1
> thread: 16 running on cpu: 3
> thread: 17 running on cpu: 7
> thread: 18 running on cpu: 3
> thread: 19 running on cpu: 5
> thread: 19 running on cpu: 2
> thread: 21 running on cpu: 2
> thread: 22 running on cpu: 7
> …
> 
> cheers