Messages in this thread Patch in this message | | | Date | Tue, 6 Feb 2024 16:56:02 +0800 | Subject | Re: [PATCH v3 1/4] sched/fair: add SD_CLUSTER in comments | From | kuiliang Shi <> |
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On 2/6/24 10:46 AM, Ricardo Neri wrote: > On Fri, Feb 02, 2024 at 03:27:32PM +0100, Valentin Schneider wrote: >> >> Subject nit: the prefix should be sched/topology >> >> On 01/02/24 19:54, alexs@kernel.org wrote: >>> From: Alex Shi <alexs@kernel.org> >>> >>> The description of SD_CLUSTER is missing. Add it. >>> >>> Signed-off-by: Alex Shi <alexs@kernel.org> >>> To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> >>> To: Valentin Schneider <vschneid@redhat.com> >>> To: Vincent Guittot <vincent.guittot@linaro.org> >>> To: Juri Lelli <juri.lelli@redhat.com> >>> To: Peter Zijlstra <peterz@infradead.org> >>> To: Ingo Molnar <mingo@redhat.com> >>> --- >>> kernel/sched/topology.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c >>> index 10d1391e7416..8b45f16a1890 100644 >>> --- a/kernel/sched/topology.c >>> +++ b/kernel/sched/topology.c >>> @@ -1554,6 +1554,7 @@ static struct cpumask ***sched_domains_numa_masks; >>> * function: >>> * >>> * SD_SHARE_CPUCAPACITY - describes SMT topologies >>> + * SD_CLUSTER - describes CPU Cluster topologies >> >> So I know this is the naming we've gone for the "Cluster" naming, but this >> comment isn't really explaining anything. >> >> include/linux/sched/sd_flags.h has a bit more info already: >> * Domain members share CPU cluster (LLC tags or L2 cache) > > I also thought of this, but I didn't want to suggest to repeat in topolog.c > what is described in sd_flags.h. > > Maybe it is better to remove the descriptions of all flags here and instead > direct the reader to sd_flags.h?
yes, good idea for getting their meaning directly from the header file. So is it fine for next sending?
sched/fair: remove duplicate comments for SD_ flags
Originally, it missed SD_CLUSTER flag description, but comparing to copy the flags meaning from sd_flags.h, reader is better to get info from there.
Keep SD_ASYM_PACKING unchange for a point from another way.
Signed-off-by: Alex Shi <alexs@kernel.org> To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> To: Valentin Schneider <vschneid@redhat.com> To: Vincent Guittot <vincent.guittot@linaro.org> To: Juri Lelli <juri.lelli@redhat.com> To: Peter Zijlstra <peterz@infradead.org> To: Ingo Molnar <mingo@redhat.com>
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 10d1391e7416..96a24bf954ad 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1551,11 +1551,7 @@ static struct cpumask ***sched_domains_numa_masks; * * These flags are purely descriptive of the topology and do not prescribe * behaviour. Behaviour is artificial and mapped in the below sd_init() - * function: - * - * SD_SHARE_CPUCAPACITY - describes SMT topologies - * SD_SHARE_PKG_RESOURCES - describes shared caches - * SD_NUMA - describes NUMA topologies + * function, for details in include/linux/sched/sd_flags.h: * * Odd one out, which beside describing the topology has a quirk also * prescribes the desired behaviour that goes along with it: >> >> I had to go through a bit of git history to remember what the CLUSTER thing >> was about, how about this: >> >> * SD_CLUSTER - describes shared shared caches, cache tags or busses > > AFAIK, this describes a subset of CPUs in the package that share a > resource, likely L2 cache. > >> * SD_SHARE_PKG_RESOURCES - describes shared LLC cache >> >> And looking at this it would make sense to: >> rename SD_CLUSTER into SD_SHARE_PKG_RESOURCES > > but not all CPUs in the package share the resource > >> rename SD_SHARE_PKG_RESOURCES into SD_SHARE_LLC >> but that's another topic... >>
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