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Wed, 15 Oct 2025 16:25:41 +0000 Message-ID: <15b871f2-49b8-4b62-926d-31f93ad49f51@intel.com> Date: Thu, 16 Oct 2025 00:25:27 +0800 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 04/19] sched/fair: Introduce a static key to enable cache aware only for multi LLCs To: Peter Zijlstra , Tim Chen CC: Ingo Molnar , K Prateek Nayak , "Gautham R . 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>> __read_mostly unsigned int llc_imb_pct = 20; >> >> +DEFINE_STATIC_KEY_FALSE(sched_cache_allowed); >> + >> +static inline bool sched_cache_enabled(void) >> +{ >> + return sched_feat(SCHED_CACHE) && >> + static_branch_likely(&sched_cache_allowed); >> +} > > Urgh; do we really need _2_ static keys stacked for this? I'm thinking > one should be well enough. SCHED_CACHE allows user space to turn on/off the feature at runtime, while sched_cache_allow is a hardware capability. This capability is disabled if there are no multiple LLCs within one node. I’m not sure if using one key could support the above two scenarios. thanks, Chenyu