Re: [PATCH 1/5] rteval: systopology.py: Add support for systems that don't have Numa

[Punit Agrawal <punitagrawal@gmail.com>]

Hi John,

John Kacur <jkacur@redhat.com> writes:

> On Wed, 1 Sep 2021, Punit Agrawal wrote:
>
>> From: Punit Agrawal <punit1.agrawal@toshiba.co.jp>
>> 
>> Certain systems such as Arm v7 do not have support for Numa nodes,
>> i.e., "/sys/devices/system/node*" does not exist. Instead of erroring
>> out in this situation, it would be better if rteval could use
>> alternate sources to get the system topology and memory information.
>> 
>> Introduce the notion of a fake Numa node (as a class) which is used
>> when no numa nodes are found on the system. Other than the
>> constructor, it provides the same interface as the existing NumaNode
>> class so existing users should work without any changes.
>> 
>> Signed-off-by: Punit Agrawal <punit1.agrawal@toshiba.co.jp>
>> ---
>>  rteval/systopology.py | 38 ++++++++++++++++++++++++++++++++------
>>  1 file changed, 32 insertions(+), 6 deletions(-)
>> 
>> diff --git a/rteval/systopology.py b/rteval/systopology.py
>> index c61ec1a58514..7ce9a8c4f707 100644
>> --- a/rteval/systopology.py
>> +++ b/rteval/systopology.py
>> @@ -191,6 +191,31 @@ class NumaNode:
>>          """ return list of cpus for this node """
>>          return self.cpus.getcpulist()
>>  
>> +class FakeNumaNode(NumaNode):
>> +    """class representing a fake NUMA node. The fake NUMA node is used on
>> +    systems which don't have NUMA enabled (no
>> +    /sys/devices/system/node) such as Arm v7
>> +
>> +    """
>> +
>> +    cpupath = '/sys/devices/system/cpu'
>> +    mempath = '/proc/meminfo'
>> +
>> +    def __init__(self):
>> +        self.nodeid = 0
>> +        self.cpus = CpuList(sysread(FakeNumaNode.cpupath, "possible"))
>> +        self.getmeminfo()
>> +
>> +    def getmeminfo(self):
>> +        self.meminfo = {}
>> +        for l in open(FakeNumaNode.mempath, "r"):
>> +            elements = l.split()
>> +            key = elements[0][0:-1]
>> +            val = int(elements[1])
>> +            if len(elements) == 3 and elements[2] == "kB":
>> +                val *= 1024
>> +            self.meminfo[key] = val
>> +
>>  #
>>  # Class to abstract the system topology of numa nodes and cpus
>>  #
>> @@ -238,12 +263,13 @@ class SysTopology:
>>  
>>      def getinfo(self):
>>          nodes = glob.glob(os.path.join(SysTopology.nodepath, 'node[0-9]*'))
>> -        if not nodes:
>> -            raise RuntimeError("No valid nodes found in %s!" % SysTopology.nodepath)
>> -        nodes.sort()
>> -        for n in nodes:
>> -            node = int(os.path.basename(n)[4:])
>> -            self.nodes[node] = NumaNode(n)
>> +        if nodes:
>> +            nodes.sort()
>> +            for n in nodes:
>> +                node = int(os.path.basename(n)[4:])
>> +                self.nodes[node] = NumaNode(n)
>> +        else:
>> +            self.nodes[0] = FakeNumaNode()
>>  
>>      def getnodes(self):
>>          return list(self.nodes.keys())
>> -- 
>> 2.32.0
>> 
>> 
>
> This is quite clever. I am just going to rename Fake to Sim as short for 
> simulated, but other than that.
>
> Signed-off-by: John Kacur <jkacur@redhat.com>

Thanks for taking a look.

I'll take a look at the updates you sent and respond there as
appropriate.

Regards,
Punit