[PATCH v2] tuna: Fix get_nr_cpus to return configured cpus

[Leah Leshchinsky]

The get_nr_cpus() function currently returns the number of enabled cpus.

In order to calculate the correct affinity, get_nr_cpus() should return
the total number of cpus configured on the system, including disabled
cpus.

Fix this by having get_nr_cpus() return SC_NPROCESSORS_CONF, rather than
procfs.cpuinfo().nr_cpus.

Small fix: Docstring

Signed-off-by: Leah Leshchinsky <lleshchi(a)redhat.com&gt;

diff --git a/tuna-cmd.py b/tuna-cmd.py
index 2b6e91bd0104..ac21481df554 100755
--- a/tuna-cmd.py
+++ b/tuna-cmd.py
@@ -105,13 +105,13 @@ def usage():
 
 
 def get_nr_cpus():
+    """ Get all cpus including disabled cpus """
     global nr_cpus
     if nr_cpus:
         return nr_cpus
-    nr_cpus = procfs.cpuinfo().nr_cpus
+    nr_cpus = os.sysconf('SC_NPROCESSORS_CONF')
     return nr_cpus
 
-
 nics = None
 
 
@@ -196,9 +196,7 @@ def format_affinity(affinity):
     if len(affinity) <= 4:
         return ",".join(str(a) for a in affinity)
 
-    # We need the number of cpus on a system, including disabled ones
-    ncpus = os.sysconf('SC_NPROCESSORS_CONF')
-    return ",".join(str(hex(a)) for a in procfs.hexbitmask(affinity, ncpus))
+    return ",".join(str(hex(a)) for a in procfs.hexbitmask(affinity,
get_nr_cpus()))
 
 def ps_show_thread(pid, affect_children, ps, has_ctxt_switch_info, sock_inodes,
                    sock_inode_re, cgroups):
-- 
2.27.0

[John Kacur]

On Fri, 4 Feb 2022, Leah Leshchinsky wrote:

>  The get_nr_cpus() function currently returns the number of enabled
> cpus.
>  
>  In order to calculate the correct affinity, get_nr_cpus() should return
>  the total number of cpus configured on the system, including disabled
>  cpus.
>  
>  Fix this by having get_nr_cpus() return SC_NPROCESSORS_CONF, rather than
>  procfs.cpuinfo().nr_cpus.
>  
>  Small fix: Docstring
>  
>  Signed-off-by: Leah Leshchinsky <lleshchi(a)redhat.com&gt;
>  
>  diff --git a/tuna-cmd.py b/tuna-cmd.py
>  index 2b6e91bd0104..ac21481df554 100755
>  --- a/tuna-cmd.py
>  +++ b/tuna-cmd.py
>  @@ -105,13 +105,13 @@ def usage():
>   
>   
>   def get_nr_cpus():
>  +    """ Get all cpus including disabled cpus """
>       global nr_cpus
>       if nr_cpus:
>           return nr_cpus
>  -    nr_cpus = procfs.cpuinfo().nr_cpus
>  +    nr_cpus = os.sysconf('SC_NPROCESSORS_CONF')
>       return nr_cpus
>   
>  -
>   nics = None
>   
>   
>  @@ -196,9 +196,7 @@ def format_affinity(affinity):
>       if len(affinity) <= 4:
>           return ",".join(str(a) for a in affinity)
>   
>  -    # We need the number of cpus on a system, including disabled ones
>  -    ncpus = os.sysconf('SC_NPROCESSORS_CONF')
>  -    return ",".join(str(hex(a)) for a in procfs.hexbitmask(affinity, ncpus))
>  +    return ",".join(str(hex(a)) for a in procfs.hexbitmask(affinity,
> get_nr_cpus()))
>   
>   def ps_show_thread(pid, affect_children, ps, has_ctxt_switch_info, sock_inodes,
>                      sock_inode_re, cgroups):
>  --  
- small edit of commit message
Signed-off-by: John Kacur <jkacur(a)redhat.com&gt;