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Message-ID: <20120622131330.GB31884@sgi.com>
Date: Fri, 22 Jun 2012 08:13:30 -0500
From: Cliff Wickman <cpw@....com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...e.hu, x86@...nel.org
Subject: [PATCH 2/3] x86: UV BAU runtime enable and disable
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: Cliff Wickman <cpw@....com>
---
arch/x86/include/asm/uv/uv_bau.h | 2 +
arch/x86/platform/uv/tlb_uv.c | 76 +++++++++++++++++++++++++++++++--------
2 files changed, 63 insertions(+), 15 deletions(-)
Index: linus.current/arch/x86/include/asm/uv/uv_bau.h
===================================================================
--- linus.current.orig/arch/x86/include/asm/uv/uv_bau.h
+++ linus.current/arch/x86/include/asm/uv/uv_bau.h
@@ -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;
Index: linus.current/arch/x86/platform/uv/tlb_uv.c
===================================================================
--- linus.current.orig/arch/x86/platform/uv/tlb_uv.c
+++ linus.current/arch/x86/platform/uv/tlb_uv.c
@@ -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,
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_other
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_
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
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 fil
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
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;
}
--
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