Re: NSProcessInfo -processorCount, -activeProcessorCount, -physicalMemory

[Fred Kiefer]

Having an implementation for these methods would be nice, but going down
the /proc/something parsing route seems wrong to me. Why not call
sysconf() with _SC_NPROCESSORS_CONF (on my GUN/Linux system this is
defined in /usr/include/bits/confname.h).
This too is a system specific solution, but at least we use glibc
instead of doing the parsing ourselves. This should save us the problem
of adopting to a new kernel every time.

We still will need different solutions for non-Linux systems.

Fred

Scott Christley wrote:
> Hello,
> 
> Here is my suggestion for implementation of these methods in
> NSProcessInfo.  This works on systems with /proc.  I don't have access
> too many different OS'es, but this works fine on an AMD64 with 16 cores
> and 16GB memory running Redhat.
> 
> I think the ability to dynamically enable/disable cores is a somewhat OS
> specific task, so I just have -activeProcessorCount return the number of
> processors.  Maybe somebody knows more about this?
> 
> It also might be nice to add these lines into Testing/nsprocessinfo.m to
> easily display the results:
> 
>   printf("Processor count: %d\n", [pi processorCount]);
>   printf("Active processor count: %d\n", [pi activeProcessorCount]);
>   printf("Physical memory: %llu\n", [pi physicalMemory]);
> 
> 
> cheers
> Scott
> 
> 
> 
> - (NSUInteger) processorCount
> {
>   int i;
>   static NSUInteger procCount = 0;
> 
>   if (procCount != 0) return procCount;
> 
>   NSFileManager *fileManager = [NSFileManager defaultManager];
> 
>   if ([fileManager fileExistsAtPath: @"/proc/cpuinfo"]) {
>     NSString *cpuInfo = [NSString stringWithContentsOfFile:
> @"/proc/cpuinfo"];
>     NSArray *a = [cpuInfo componentsSeparatedByCharactersInSet:
> [NSCharacterSet whitespaceAndNewlineCharacterSet]];
>     // syntax is processor : #
>     // count up each one
>     for (i = 0; i < [a count]; ++i) {
>       if ([[a objectAtIndex: i] isEqualToString: @"processor"])
>         if (((i+1) < [a count]) && [[a objectAtIndex: i+1]
> isEqualToString: @":"])
>           ++procCount;
>     }
>   } else {
>     NSLog(@"Cannot determine processor count.");
>   }
> 
>   // if unable to determine, failsafe to one processor
>   if (procCount == 0) procCount = 1;
> 
>   return procCount;
> }
> 
> - (NSUInteger) activeProcessorCount
> {
>   return [self processorCount];
> }
> 
> - (unsigned long long) physicalMemory
> {
>   static NSUInteger availMem = 0;
> 
>   if (availMem != 0) return availMem;
> 
>   NSFileManager *fileManager = [NSFileManager defaultManager];
> 
>   if ([fileManager fileExistsAtPath: @"/proc/meminfo"]) {
>     NSString *memInfo = [NSString stringWithContentsOfFile:
> @"/proc/meminfo"];
>     NSRange r = [memInfo rangeOfString: @"MemTotal:"];
>     if (r.location == NSNotFound) {
>       NSLog(@"Cannot determine amount of physical memory.");
>       return 0;
>     }
>     NSString *s = [[memInfo substringFromIndex: (r.location + r.length)]
>                     stringByTrimmingCharactersInSet: [NSCharacterSet
> whitespaceAndNewlineCharacterSet]];
>     NSArray *a = [s componentsSeparatedByString: @" "];
>     s = [a objectAtIndex: 0];
>     availMem = (NSUInteger)[s longLongValue];
>     availMem *= 1024;
>   } else {
>     NSLog(@"Cannot determine amount of physical memory.");
>   }
> 
>   return availMem;
> }