Re: [PATCH 3/3] rteval: systopology.py: Add support for systems that don't have Numa

[Punit Agrawal <punitagrawal@gmail.com>]

John Kacur <jkacur@redhat.com> writes:

> 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>
> - Renamed Fake to Sim for simulated
> Signed-off-by: John Kacur <jkacur@redhat.com>
> ---
>  rteval/systopology.py | 37 +++++++++++++++++++++++++++++++------
>  1 file changed, 31 insertions(+), 6 deletions(-)
>
> diff --git a/rteval/systopology.py b/rteval/systopology.py
> index c61ec1a58514..3c996048f8c1 100644
> --- a/rteval/systopology.py
> +++ b/rteval/systopology.py
> @@ -191,6 +191,30 @@ class NumaNode:
>          """ return list of cpus for this node """
>          return self.cpus.getcpulist()
>  
> +class SimNumaNode(NumaNode):
> +    """class representing a simulated NUMA node.
> +    For 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(SimNumaNode.cpupath, "possible"))
> +        self.getmeminfo()
> +
> +    def getmeminfo(self):
> +        self.meminfo = {}
> +        for l in open(SimNumaNode.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 +262,13 @@ 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] = SimNumaNode()
>  
>      def getnodes(self):
>          return list(self.nodes.keys())

The name changes look good and passed a test run of rteval on a system
with no numa nodes.

Thanks,
Punit