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Commit a9110b55 authored by Vikas Shivappa's avatar Vikas Shivappa Committed by Thomas Gleixner
Browse files

x86/intel_rdt: Modify the intel_pqr_state for better performance 



Currently we have pqr_state and rdt_default_state which store the cached
CLOSID/RMIDs and the user configured cpu default values respectively. We
touch both of these during context switch. Put all of them in one
structure so that we can spare a cache line.

Reported-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: sai.praneeth.prakhya@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Link: http://lkml.kernel.org/r/1502304395-7166-3-git-send-email-vikas.shivappa@linux.intel.com
parent eda61c26

arch/x86/include/asm/intel_rdt_sched.h

+17 −13
Original line number Diff line number Diff line
@@ -10,8 +10,10 @@ 


/**

 * struct intel_pqr_state - State cache for the PQR MSR

 * @rmid:		The cached Resource Monitoring ID

 * @closid:		The cached Class Of Service ID

 * @cur_rmid:		The cached Resource Monitoring ID

 * @cur_closid:	The cached Class Of Service ID

 * @default_rmid:	The user assigned Resource Monitoring ID

 * @default_closid:	The user assigned cached Class Of Service ID

 *

 * The upper 32 bits of IA32_PQR_ASSOC contain closid and the

 * lower 10 bits rmid. The update to IA32_PQR_ASSOC always
@@ -22,12 +24,13 @@ 
 * not change.

 */

struct intel_pqr_state {

	u32			rmid;

	u32			closid;

	u32			cur_rmid;

	u32			cur_closid;

	u32			default_rmid;

	u32			default_closid;

};



DECLARE_PER_CPU(struct intel_pqr_state, pqr_state);

DECLARE_PER_CPU_READ_MOSTLY(struct intel_pqr_state, rdt_cpu_default);



DECLARE_STATIC_KEY_FALSE(rdt_enable_key);

DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
@@ -49,8 +52,9 @@ DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key); 
 */

static void __intel_rdt_sched_in(void)

{

	struct intel_pqr_state newstate = this_cpu_read(rdt_cpu_default);

	struct intel_pqr_state *curstate = this_cpu_ptr(&pqr_state);

	struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);

	u32 closid = state->default_closid;

	u32 rmid = state->default_rmid;



	/*

	 * If this task has a closid/rmid assigned, use it.
@@ -58,18 +62,18 @@ static void __intel_rdt_sched_in(void) 
	 */

	if (static_branch_likely(&rdt_alloc_enable_key)) {

		if (current->closid)

			newstate.closid = current->closid;

			closid = current->closid;

	}



	if (static_branch_likely(&rdt_mon_enable_key)) {

		if (current->rmid)

			newstate.rmid = current->rmid;

			rmid = current->rmid;

	}



	if (newstate.closid != curstate->closid ||

	    newstate.rmid != curstate->rmid) {

		*curstate = newstate;

		wrmsr(IA32_PQR_ASSOC, newstate.rmid, newstate.closid);

	if (closid != state->cur_closid || rmid != state->cur_rmid) {

		state->cur_closid = closid;

		state->cur_rmid = rmid;

		wrmsr(IA32_PQR_ASSOC, rmid, closid);

	}

}

arch/x86/kernel/cpu/intel_rdt.c

+4 −6
Original line number Diff line number Diff line
@@ -47,8 +47,6 @@ DEFINE_MUTEX(rdtgroup_mutex); 
 */

DEFINE_PER_CPU(struct intel_pqr_state, pqr_state);



DEFINE_PER_CPU_READ_MOSTLY(struct intel_pqr_state, rdt_cpu_default);



/*

 * Used to store the max resource name width and max resource data width

 * to display the schemata in a tabular format
@@ -550,10 +548,10 @@ static void clear_closid_rmid(int cpu) 
{

	struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);



	per_cpu(rdt_cpu_default.closid, cpu) = 0;

	per_cpu(rdt_cpu_default.rmid, cpu) = 0;

	state->closid = 0;

	state->rmid = 0;

	state->default_closid = 0;

	state->default_rmid = 0;

	state->cur_closid = 0;

	state->cur_rmid = 0;

	wrmsr(IA32_PQR_ASSOC, 0, 0);

}

arch/x86/kernel/cpu/intel_rdt_rdtgroup.c

+5 −5
Original line number Diff line number Diff line
@@ -202,8 +202,8 @@ static void update_cpu_closid_rmid(void *info) 
	struct rdtgroup *r = info;



	if (r) {

		this_cpu_write(rdt_cpu_default.closid, r->closid);

		this_cpu_write(rdt_cpu_default.rmid, r->mon.rmid);

		this_cpu_write(pqr_state.default_closid, r->closid);

		this_cpu_write(pqr_state.default_rmid, r->mon.rmid);

	}



	/*
@@ -1733,7 +1733,7 @@ static int rdtgroup_rmdir_mon(struct kernfs_node *kn, struct rdtgroup *rdtgrp, 


	/* Update per cpu rmid of the moved CPUs first */

	for_each_cpu(cpu, &rdtgrp->cpu_mask)

		per_cpu(rdt_cpu_default.rmid, cpu) = prdtgrp->mon.rmid;

		per_cpu(pqr_state.default_rmid, cpu) = prdtgrp->mon.rmid;

	/*

	 * Update the MSR on moved CPUs and CPUs which have moved

	 * task running on them.
@@ -1774,8 +1774,8 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp, 


	/* Update per cpu closid and rmid of the moved CPUs first */

	for_each_cpu(cpu, &rdtgrp->cpu_mask) {

		per_cpu(rdt_cpu_default.closid, cpu) = rdtgroup_default.closid;

		per_cpu(rdt_cpu_default.rmid, cpu) = rdtgroup_default.mon.rmid;

		per_cpu(pqr_state.default_closid, cpu) = rdtgroup_default.closid;

		per_cpu(pqr_state.default_rmid, cpu) = rdtgroup_default.mon.rmid;

	}



	/*