drivers/iommu/intel/perf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * perf.c - performance monitor
   4  *
   5  * Copyright (C) 2021 Intel Corporation
   6  *
   7  * Author: Lu Baolu <baolu.lu@linux.intel.com>
   8  *         Fenghua Yu <fenghua.yu@intel.com>
   9  */
  10
  11 #include <linux/spinlock.h>
  12
  13 #include "iommu.h"
  14 #include "perf.h"
  15
  16 static DEFINE_SPINLOCK(latency_lock);
  17
  18 bool dmar_latency_enabled(struct intel_iommu *iommu, enum latency_type type)
  19 {
  20         struct latency_statistic *lstat = iommu->perf_statistic;
  21
  22         return lstat && lstat[type].enabled;
  23 }
  24
  25 int dmar_latency_enable(struct intel_iommu *iommu, enum latency_type type)
  26 {
  27         struct latency_statistic *lstat;
  28         unsigned long flags;
  29         int ret = -EBUSY;
  30
  31         if (dmar_latency_enabled(iommu, type))
  32                 return 0;
  33
  34         spin_lock_irqsave(&latency_lock, flags);
  35         if (!iommu->perf_statistic) {
  36                 iommu->perf_statistic = kcalloc(DMAR_LATENCY_NUM, sizeof(*lstat),
  37                                                 GFP_ATOMIC);
  38                 if (!iommu->perf_statistic) {
  39                         ret = -ENOMEM;
  40                         goto unlock_out;
  41                 }
  42         }
  43
  44         lstat = iommu->perf_statistic;
  45
  46         if (!lstat[type].enabled) {
  47                 lstat[type].enabled = true;
  48                 lstat[type].counter[COUNTS_MIN] = UINT_MAX;
  49                 ret = 0;
  50         }
  51 unlock_out:
  52         spin_unlock_irqrestore(&latency_lock, flags);
  53
  54         return ret;
  55 }
  56
  57 void dmar_latency_disable(struct intel_iommu *iommu, enum latency_type type)
  58 {
  59         struct latency_statistic *lstat = iommu->perf_statistic;
  60         unsigned long flags;
  61
  62         if (!dmar_latency_enabled(iommu, type))
  63                 return;
  64
  65         spin_lock_irqsave(&latency_lock, flags);
  66         memset(&lstat[type], 0, sizeof(*lstat) * DMAR_LATENCY_NUM);
  67         spin_unlock_irqrestore(&latency_lock, flags);
  68 }
  69
  70 void dmar_latency_update(struct intel_iommu *iommu, enum latency_type type, u64 latency)
  71 {
  72         struct latency_statistic *lstat = iommu->perf_statistic;
  73         unsigned long flags;
  74         u64 min, max;
  75
  76         if (!dmar_latency_enabled(iommu, type))
  77                 return;
  78
  79         spin_lock_irqsave(&latency_lock, flags);
  80         if (latency < 100)
  81                 lstat[type].counter[COUNTS_10e2]++;
  82         else if (latency < 1000)
  83                 lstat[type].counter[COUNTS_10e3]++;
  84         else if (latency < 10000)
  85                 lstat[type].counter[COUNTS_10e4]++;
  86         else if (latency < 100000)
  87                 lstat[type].counter[COUNTS_10e5]++;
  88         else if (latency < 1000000)
  89                 lstat[type].counter[COUNTS_10e6]++;
  90         else if (latency < 10000000)
  91                 lstat[type].counter[COUNTS_10e7]++;
  92         else
  93                 lstat[type].counter[COUNTS_10e8_plus]++;
  94
  95         min = lstat[type].counter[COUNTS_MIN];
  96         max = lstat[type].counter[COUNTS_MAX];
  97         lstat[type].counter[COUNTS_MIN] = min_t(u64, min, latency);
  98         lstat[type].counter[COUNTS_MAX] = max_t(u64, max, latency);
  99         lstat[type].counter[COUNTS_SUM] += latency;
 100         lstat[type].samples++;
 101         spin_unlock_irqrestore(&latency_lock, flags);
 102 }
 103
 104 static char *latency_counter_names[] = {
 105         "                  <0.1us",
 106         "   0.1us-1us", "    1us-10us", "  10us-100us",
 107         "   100us-1ms", "    1ms-10ms", "      >=10ms",
 108         "     min(us)", "     max(us)", " average(us)"
 109 };
 110
 111 static char *latency_type_names[] = {
 112         "   inv_iotlb", "  inv_devtlb", "     inv_iec",
 113         "     svm_prq"
 114 };
 115
 116 int dmar_latency_snapshot(struct intel_iommu *iommu, char *str, size_t size)
 117 {
 118         struct latency_statistic *lstat = iommu->perf_statistic;
 119         unsigned long flags;
 120         int bytes = 0, i, j;
 121
 122         memset(str, 0, size);
 123
 124         for (i = 0; i < COUNTS_NUM; i++)
 125                 bytes += snprintf(str + bytes, size - bytes,
 126                                   "%s", latency_counter_names[i]);
 127
 128         spin_lock_irqsave(&latency_lock, flags);
 129         for (i = 0; i < DMAR_LATENCY_NUM; i++) {
 130                 if (!dmar_latency_enabled(iommu, i))
 131                         continue;
 132
 133                 bytes += snprintf(str + bytes, size - bytes,
 134                                   "\n%s", latency_type_names[i]);
 135
 136                 for (j = 0; j < COUNTS_NUM; j++) {
 137                         u64 val = lstat[i].counter[j];
 138
 139                         switch (j) {
 140                         case COUNTS_MIN:
 141                                 if (val == UINT_MAX)
 142                                         val = 0;
 143                                 else
 144                                         val = div_u64(val, 1000);
 145                                 break;
 146                         case COUNTS_MAX:
 147                                 val = div_u64(val, 1000);
 148                                 break;
 149                         case COUNTS_SUM:
 150                                 if (lstat[i].samples)
 151                                         val = div_u64(val, (lstat[i].samples * 1000));
 152                                 else
 153                                         val = 0;
 154                                 break;
 155                         default:
 156                                 break;
 157                         }
 158
 159                         bytes += snprintf(str + bytes, size - bytes,
 160                                           "%12lld", val);
 161                 }
 162         }
 163         spin_unlock_irqrestore(&latency_lock, flags);
 164
 165         return bytes;
 166 }