Re: [uml-devel] sysconf(_SC_NPROCESSORS_CONF) returning zero

[Stanislav Meduna <stano@meduna.org>]

Jeff Dike wrote:

> I see it counting cpu<n> lines in /proc/stat, which is what I'm
> seeing.  It will also look at /proc/cpuinfo.  Can you strace your
> version and see if it's looking there at all?

No.. looks like they changed the method:

open("/sys/devices/system/cpu", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_DIRECTORY|0x80
000) = 3
fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
fcntl64(3, F_GETFD)                     = 0x1 (flags FD_CLOEXEC)
getdents64(3, /* 5 entries */, 4096)    = 144
getdents64(3, /* 0 entries */, 4096)    = 0
close(3)                                = 0

No reference to /proc/stat nor /proc/cpuinfo.

# ls -l /sys/devices/system/cpu
-r--r--r-- 1 root root 4096 2008-08-04 23:51 online
-r--r--r-- 1 root root 4096 2008-08-04 23:51 possible
-r--r--r-- 1 root root 4096 2008-08-04 23:51 present

# cat /sys/devices/system/cpu/online
0
# cat /sys/devices/system/cpu/possible
0
# cat /sys/devices/system/cpu/present
0


On another Linux (real, 2.6.18) this looks completely
different:

$ ls -l /sys/devices/system/cpu
total 0
drwxr-xr-x 4 root root 0 2008-08-04 23:53 cpu0


$ ls -l /sys/devices/system/cpu/cpu0/
total 0
drwxr-xr-x 5 root root    0 2007-06-11 09:30 cache
-r-------- 1 root root 4096 2008-08-04 23:53 crash_notes
drwxr-xr-x 2 root root    0 2007-06-11 09:30 topology


Well.. so this is an interface definition problem.. now who has
changet something and did not tell the others..


-- 
                                   Stano

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