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// SPDX-License-Identifier: GPL-2.0
/*
* perf.c - performance monitor
*
* Copyright (C) 2021 Intel Corporation
*
* Author: Lu Baolu <baolu.lu@linux.intel.com>
* Fenghua Yu <fenghua.yu@intel.com>
*/
#include <linux/spinlock.h>
#include <linux/intel-iommu.h>
#include "perf.h"
static DEFINE_SPINLOCK(latency_lock);
bool dmar_latency_enabled(struct intel_iommu *iommu, enum latency_type type)
{
struct latency_statistic *lstat = iommu->perf_statistic;
return lstat && lstat[type].enabled;
}
int dmar_latency_enable(struct intel_iommu *iommu, enum latency_type type)
{
struct latency_statistic *lstat;
unsigned long flags;
int ret = -EBUSY;
if (dmar_latency_enabled(iommu, type))
return 0;
spin_lock_irqsave(&latency_lock, flags);
if (!iommu->perf_statistic) {
iommu->perf_statistic = kzalloc(sizeof(*lstat) * DMAR_LATENCY_NUM,
GFP_ATOMIC);
if (!iommu->perf_statistic) {
ret = -ENOMEM;
goto unlock_out;
}
}
lstat = iommu->perf_statistic;
if (!lstat[type].enabled) {
lstat[type].enabled = true;
lstat[type].counter[COUNTS_MIN] = UINT_MAX;
ret = 0;
}
unlock_out:
spin_unlock_irqrestore(&latency_lock, flags);
return ret;
}
void dmar_latency_disable(struct intel_iommu *iommu, enum latency_type type)
{
struct latency_statistic *lstat = iommu->perf_statistic;
unsigned long flags;
if (!dmar_latency_enabled(iommu, type))
return;
spin_lock_irqsave(&latency_lock, flags);
memset(&lstat[type], 0, sizeof(*lstat) * DMAR_LATENCY_NUM);
spin_unlock_irqrestore(&latency_lock, flags);
}
void dmar_latency_update(struct intel_iommu *iommu, enum latency_type type, u64 latency)
{
struct latency_statistic *lstat = iommu->perf_statistic;
unsigned long flags;
u64 min, max;
if (!dmar_latency_enabled(iommu, type))
return;
spin_lock_irqsave(&latency_lock, flags);
if (latency < 100)
lstat[type].counter[COUNTS_10e2]++;
else if (latency < 1000)
lstat[type].counter[COUNTS_10e3]++;
else if (latency < 10000)
lstat[type].counter[COUNTS_10e4]++;
else if (latency < 100000)
lstat[type].counter[COUNTS_10e5]++;
else if (latency < 1000000)
lstat[type].counter[COUNTS_10e6]++;
else if (latency < 10000000)
lstat[type].counter[COUNTS_10e7]++;
else
lstat[type].counter[COUNTS_10e8_plus]++;
min = lstat[type].counter[COUNTS_MIN];
max = lstat[type].counter[COUNTS_MAX];
lstat[type].counter[COUNTS_MIN] = min_t(u64, min, latency);
lstat[type].counter[COUNTS_MAX] = max_t(u64, max, latency);
lstat[type].counter[COUNTS_SUM] += latency;
lstat[type].samples++;
spin_unlock_irqrestore(&latency_lock, flags);
}
static char *latency_counter_names[] = {
" <0.1us",
" 0.1us-1us", " 1us-10us", " 10us-100us",
" 100us-1ms", " 1ms-10ms", " >=10ms",
" min(us)", " max(us)", " average(us)"
};
static char *latency_type_names[] = {
" inv_iotlb", " inv_devtlb", " inv_iec",
" svm_prq"
};
int dmar_latency_snapshot(struct intel_iommu *iommu, char *str, size_t size)
{
struct latency_statistic *lstat = iommu->perf_statistic;
unsigned long flags;
int bytes = 0, i, j;
memset(str, 0, size);
for (i = 0; i < COUNTS_NUM; i++)
bytes += snprintf(str + bytes, size - bytes,
"%s", latency_counter_names[i]);
spin_lock_irqsave(&latency_lock, flags);
for (i = 0; i < DMAR_LATENCY_NUM; i++) {
if (!dmar_latency_enabled(iommu, i))
continue;
bytes += snprintf(str + bytes, size - bytes,
"\n%s", latency_type_names[i]);
for (j = 0; j < COUNTS_NUM; j++) {
u64 val = lstat[i].counter[j];
switch (j) {
case COUNTS_MIN:
if (val == UINT_MAX)
val = 0;
else
val = div_u64(val, 1000);
break;
case COUNTS_MAX:
val = div_u64(val, 1000);
break;
case COUNTS_SUM:
if (lstat[i].samples)
val = div_u64(val, (lstat[i].samples * 1000));
else
val = 0;
break;
default:
break;
}
bytes += snprintf(str + bytes, size - bytes,
"%12lld", val);
}
}
spin_unlock_irqrestore(&latency_lock, flags);
return bytes;
}
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