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Commit 26ef8577 authored by Cliff Wickman's avatar Cliff Wickman Committed by Ingo Molnar
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x86/uv: Implement UV BAU runtime enable and disable control via /proc/sgi_uv/ 



This patch enables the BAU to be turned on or off dynamically.

  echo "on"  > /proc/sgi_uv/ptc_statistics
  echo "off" > /proc/sgi_uv/ptc_statistics

The system may be booted with or without the nobau option.

Whether the system currently has the BAU off can be seen in
the /proc file -- normally with the baustats script.
Each cpu will have a 1 in the bauoff field if the BAU was turned
off, so baustats will give a count of cpus that have it off.

Signed-off-by: default avatarCliff Wickman <cpw@sgi.com>
Link: http://lkml.kernel.org/r/20120622131330.GB31884@sgi.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 11cab711

arch/x86/include/asm/uv/uv_bau.h

+2 −0
Original line number Diff line number Diff line
@@ -520,6 +520,7 @@ struct ptc_stats { 
	unsigned long	s_uv2_wars;		/* uv2 workaround, perm. busy */

	unsigned long	s_uv2_wars_hw;		/* uv2 workaround, hiwater */

	unsigned long	s_uv2_war_waits;	/* uv2 workaround, long waits */

	unsigned long   s_enters;		/* entries to the driver */

	/* destination statistics */

	unsigned long	d_alltlb;		/* times all tlb's on this

						   cpu were flushed */
@@ -586,6 +587,7 @@ struct bau_control { 
	int			timeout_tries;

	int			ipi_attempts;

	int			conseccompletes;

	short			nobau;

	int			baudisabled;

	int			set_bau_off;

	short			cpu;

arch/x86/platform/uv/tlb_uv.c

+61 −15
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ static int timeout_base_ns[] = { 


static int timeout_us;

static int nobau;

static int nobau_perm;

static int baudisabled;

static spinlock_t disable_lock;

static cycles_t congested_cycles;
@@ -120,6 +121,40 @@ static DEFINE_PER_CPU(struct ptc_stats, ptcstats); 
static DEFINE_PER_CPU(struct bau_control, bau_control);

static DEFINE_PER_CPU(cpumask_var_t, uv_flush_tlb_mask);



static void

set_bau_on(void)

{

	int cpu;

	struct bau_control *bcp;



	if (nobau_perm) {

		pr_info("BAU not initialized; cannot be turned on\n");

		return;

	}

	nobau = 0;

	for_each_present_cpu(cpu) {

		bcp = &per_cpu(bau_control, cpu);

		bcp->nobau = 0;

	}

	pr_info("BAU turned on\n");

	return;

}



static void

set_bau_off(void)

{

	int cpu;

	struct bau_control *bcp;



	nobau = 1;

	for_each_present_cpu(cpu) {

		bcp = &per_cpu(bau_control, cpu);

		bcp->nobau = 1;

	}

	pr_info("BAU turned off\n");

	return;

}



/*

 * Determine the first node on a uvhub. 'Nodes' are used for kernel

 * memory allocation.
@@ -1079,12 +1114,12 @@ const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask, 
	struct ptc_stats *stat;

	struct bau_control *bcp;



	/* kernel was booted 'nobau' */

	if (nobau)

		return cpumask;



	bcp = &per_cpu(bau_control, cpu);

	stat = bcp->statp;

	stat->s_enters++;



	if (bcp->nobau)

		return cpumask;



	/* bau was disabled due to slow response */

	if (bcp->baudisabled) {
@@ -1338,29 +1373,32 @@ static inline unsigned long long usec_2_cycles(unsigned long microsec) 
static int ptc_seq_show(struct seq_file *file, void *data)

{

	struct ptc_stats *stat;

	struct bau_control *bcp;

	int cpu;



	cpu = *(loff_t *)data;

	if (!cpu) {

		seq_printf(file,

			"# cpu sent stime self locals remotes ncpus localhub ");

		"# cpu bauoff sent stime self locals remotes ncpus localhub ");

		seq_printf(file,

			"remotehub numuvhubs numuvhubs16 numuvhubs8 ");

		seq_printf(file,

		    "numuvhubs4 numuvhubs2 numuvhubs1 dto snacks retries rok ");

		seq_printf(file,

			"resetp resett giveup sto bz throt swack recv rtime ");

			"resetp resett giveup sto bz throt enters swack recv rtime ");

		seq_printf(file,

			"all one mult none retry canc nocan reset rcan ");

		seq_printf(file,

			"disable enable wars warshw warwaits\n");

	}

	if (cpu < num_possible_cpus() && cpu_online(cpu)) {

		stat = &per_cpu(ptcstats, cpu);

		bcp = &per_cpu(bau_control, cpu);

		stat = bcp->statp;

		/* source side statistics */

		seq_printf(file,

			"cpu %d %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld ",

			   cpu, stat->s_requestor, cycles_2_us(stat->s_time),

			   "cpu %d %d %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld ",

			   cpu, bcp->nobau, stat->s_requestor,

			   cycles_2_us(stat->s_time),

			   stat->s_ntargself, stat->s_ntarglocals,

			   stat->s_ntargremotes, stat->s_ntargcpu,

			   stat->s_ntarglocaluvhub, stat->s_ntargremoteuvhub,
@@ -1369,11 +1407,11 @@ static int ptc_seq_show(struct seq_file *file, void *data) 
			   stat->s_ntarguvhub8, stat->s_ntarguvhub4,

			   stat->s_ntarguvhub2, stat->s_ntarguvhub1,

			   stat->s_dtimeout, stat->s_strongnacks);

		seq_printf(file, "%ld %ld %ld %ld %ld %ld %ld %ld ",

		seq_printf(file, "%ld %ld %ld %ld %ld %ld %ld %ld %ld ",

			   stat->s_retry_messages, stat->s_retriesok,

			   stat->s_resets_plug, stat->s_resets_timeout,

			   stat->s_giveup, stat->s_stimeout,

			   stat->s_busy, stat->s_throttles);

			   stat->s_busy, stat->s_throttles, stat->s_enters);



		/* destination side statistics */

		seq_printf(file,
@@ -1438,6 +1476,14 @@ static ssize_t ptc_proc_write(struct file *file, const char __user *user, 
		return -EFAULT;

	optstr[count - 1] = '\0';



	if (!strcmp(optstr, "on")) {

		set_bau_on();

		return count;

	} else if (!strcmp(optstr, "off")) {

		set_bau_off();

		return count;

	}



	if (strict_strtol(optstr, 10, &input_arg) < 0) {

		printk(KERN_DEBUG "%s is invalid\n", optstr);

		return -EINVAL;
@@ -1836,6 +1882,8 @@ static void __init init_per_cpu_tunables(void) 
	for_each_present_cpu(cpu) {

		bcp = &per_cpu(bau_control, cpu);

		bcp->baudisabled		= 0;

		if (nobau)

			bcp->nobau		= 1;

		bcp->statp			= &per_cpu(ptcstats, cpu);

		/* time interval to catch a hardware stay-busy bug */

		bcp->timeout_interval		= usec_2_cycles(2*timeout_us);
@@ -2069,9 +2117,6 @@ static int __init uv_bau_init(void) 
	if (!is_uv_system())

		return 0;



	if (nobau)

		return 0;



	for_each_possible_cpu(cur_cpu) {

		mask = &per_cpu(uv_flush_tlb_mask, cur_cpu);

		zalloc_cpumask_var_node(mask, GFP_KERNEL, cpu_to_node(cur_cpu));
@@ -2091,7 +2136,8 @@ static int __init uv_bau_init(void) 
	enable_timeouts();



	if (init_per_cpu(nuvhubs, uv_base_pnode)) {

		nobau = 1;

		set_bau_off();

		nobau_perm = 1;

		return 0;

	}