Messages in this thread Patch in this message | | | From | Vikas Shivappa <> | Subject | [PATCH 17/21] x86/intel_rdt/cqm: Add sched_in support | Date | Mon, 26 Jun 2017 11:56:04 -0700 |
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OS associates an RMID/CLOSid to a task by writing the per CPU IA32_PQR_ASSOC MSR when a task is scheduled in.
The sched_in code will stay as no-op unless we are running on Intel SKU which supports either resource control or monitoring and we also enable them by mounting the resctrl fs. The per cpu CLOSid/RMID values are cached and the write is performed only when a task with a different CLOSid/RMID is scheduled in.
Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> --- arch/x86/include/asm/intel_rdt_sched.h | 47 ++++++++++++++++++++++++---------- 1 file changed, 34 insertions(+), 13 deletions(-)
diff --git a/arch/x86/include/asm/intel_rdt_sched.h b/arch/x86/include/asm/intel_rdt_sched.h index 4dee77b..7c823c4 100644 --- a/arch/x86/include/asm/intel_rdt_sched.h +++ b/arch/x86/include/asm/intel_rdt_sched.h @@ -27,27 +27,31 @@ struct intel_pqr_state { DECLARE_PER_CPU(struct intel_pqr_state, pqr_state); DECLARE_PER_CPU_READ_MOSTLY(int, cpu_closid); +DECLARE_PER_CPU_READ_MOSTLY(int, cpu_rmid); DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key); +DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key); +DECLARE_STATIC_KEY_FALSE(rdt_enable_key); /* - * intel_rdt_sched_in() - Writes the task's CLOSid to IA32_PQR_MSR + * __intel_rdt_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR * * Following considerations are made so that this has minimal impact * on scheduler hot path: * - This will stay as no-op unless we are running on an Intel SKU - * which supports resource control and we enable by mounting the - * resctrl file system. - * - Caches the per cpu CLOSid values and does the MSR write only - * when a task with a different CLOSid is scheduled in. + * which supports resource control or monitoring and we enable by + * mounting the resctrl file system. + * - Caches the per cpu CLOSid/RMID values and does the MSR write only + * when a task with a different CLOSid/RMID is scheduled in. * * Must be called with preemption disabled. */ -static inline void intel_rdt_sched_in(void) +static void __intel_rdt_sched_in(void) { - if (static_branch_likely(&rdt_alloc_enable_key)) { - struct intel_pqr_state *state = this_cpu_ptr(&pqr_state); - int closid; + struct intel_pqr_state *state = this_cpu_ptr(&pqr_state); + u32 closid = 0; + u32 rmid = 0; + if (static_branch_likely(&rdt_alloc_enable_key)) { /* * If this task has a closid assigned, use it. * Else use the closid assigned to this cpu. @@ -55,14 +59,31 @@ static inline void intel_rdt_sched_in(void) closid = current->closid; if (closid == 0) closid = this_cpu_read(cpu_closid); + } + + if (static_branch_likely(&rdt_mon_enable_key)) { + /* + * If this task has a rmid assigned, use it. + * Else use the rmid assigned to this cpu. + */ + rmid = current->rmid; + if (rmid == 0) + rmid = this_cpu_read(cpu_rmid); + } - if (closid != state->closid) { - state->closid = closid; - wrmsr(IA32_PQR_ASSOC, state->rmid, closid); - } + if (closid != state->closid || rmid != state->rmid) { + state->closid = closid; + state->rmid = rmid; + wrmsr(IA32_PQR_ASSOC, rmid, closid); } } +static inline void intel_rdt_sched_in(void) +{ + if (static_branch_likely(&rdt_enable_key)) + __intel_rdt_sched_in(); +} + #else static inline void intel_rdt_sched_in(void) {} -- 1.9.1
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