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

John Kacur
2021-09-09T12:40:18Z

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>