drivers/gpu/drm/msm/msm_perf.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2013 Red Hat
   4  * Author: Rob Clark <[email protected]>
   5  */
   6
   7 /* For profiling, userspace can:
   8  *
   9  *   tail -f /sys/kernel/debug/dri/<minor>/gpu
  10  *
  11  * This will enable performance counters/profiling to track the busy time
  12  * and any gpu specific performance counters that are supported.
  13  */
  14
  15 #ifdef CONFIG_DEBUG_FS
  16
  17 #include <linux/debugfs.h>
  18
  19 #include "msm_drv.h"
  20 #include "msm_gpu.h"
  21
  22 struct msm_perf_state {
  23         struct drm_device *dev;
  24
  25         bool open;
  26         int cnt;
  27         struct mutex read_lock;
  28
  29         char buf[256];
  30         int buftot, bufpos;
  31
  32         unsigned long next_jiffies;
  33 };
  34
  35 #define SAMPLE_TIME (HZ/4)
  36
  37 /* wait for next sample time: */
  38 static int wait_sample(struct msm_perf_state *perf)
  39 {
  40         unsigned long start_jiffies = jiffies;
  41
  42         if (time_after(perf->next_jiffies, start_jiffies)) {
  43                 unsigned long remaining_jiffies =
  44                         perf->next_jiffies - start_jiffies;
  45                 int ret = schedule_timeout_interruptible(remaining_jiffies);
  46                 if (ret > 0) {
  47                         /* interrupted */
  48                         return -ERESTARTSYS;
  49                 }
  50         }
  51         perf->next_jiffies += SAMPLE_TIME;
  52         return 0;
  53 }
  54
  55 static int refill_buf(struct msm_perf_state *perf)
  56 {
  57         struct msm_drm_private *priv = perf->dev->dev_private;
  58         struct msm_gpu *gpu = priv->gpu;
  59         char *ptr = perf->buf;
  60         int rem = sizeof(perf->buf);
  61         int i, n;
  62
  63         if ((perf->cnt++ % 32) == 0) {
  64                 /* Header line: */
  65                 n = snprintf(ptr, rem, "%%BUSY");
  66                 ptr += n;
  67                 rem -= n;
  68
  69                 for (i = 0; i < gpu->num_perfcntrs; i++) {
  70                         const struct msm_gpu_perfcntr *perfcntr = &gpu->perfcntrs[i];
  71                         n = snprintf(ptr, rem, "\t%s", perfcntr->name);
  72                         ptr += n;
  73                         rem -= n;
  74                 }
  75         } else {
  76                 /* Sample line: */
  77                 uint32_t activetime = 0, totaltime = 0;
  78                 uint32_t cntrs[5];
  79                 uint32_t val;
  80                 int ret;
  81
  82                 /* sleep until next sample time: */
  83                 ret = wait_sample(perf);
  84                 if (ret)
  85                         return ret;
  86
  87                 ret = msm_gpu_perfcntr_sample(gpu, &activetime, &totaltime,
  88                                 ARRAY_SIZE(cntrs), cntrs);
  89                 if (ret < 0)
  90                         return ret;
  91
  92                 val = totaltime ? 1000 * activetime / totaltime : 0;
  93                 n = snprintf(ptr, rem, "%3d.%d%%", val / 10, val % 10);
  94                 ptr += n;
  95                 rem -= n;
  96
  97                 for (i = 0; i < ret; i++) {
  98                         /* cycle counters (I think).. convert to MHz.. */
  99                         val = cntrs[i] / 10000;
 100                         n = snprintf(ptr, rem, "\t%5d.%02d",
 101                                         val / 100, val % 100);
 102                         ptr += n;
 103                         rem -= n;
 104                 }
 105         }
 106
 107         n = snprintf(ptr, rem, "\n");
 108         ptr += n;
 109         rem -= n;
 110
 111         perf->bufpos = 0;
 112         perf->buftot = ptr - perf->buf;
 113
 114         return 0;
 115 }
 116
 117 static ssize_t perf_read(struct file *file, char __user *buf,
 118                 size_t sz, loff_t *ppos)
 119 {
 120         struct msm_perf_state *perf = file->private_data;
 121         int n = 0, ret = 0;
 122
 123         mutex_lock(&perf->read_lock);
 124
 125         if (perf->bufpos >= perf->buftot) {
 126                 ret = refill_buf(perf);
 127                 if (ret)
 128                         goto out;
 129         }
 130
 131         n = min((int)sz, perf->buftot - perf->bufpos);
 132         if (copy_to_user(buf, &perf->buf[perf->bufpos], n)) {
 133                 ret = -EFAULT;
 134                 goto out;
 135         }
 136
 137         perf->bufpos += n;
 138         *ppos += n;
 139
 140 out:
 141         mutex_unlock(&perf->read_lock);
 142         if (ret)
 143                 return ret;
 144         return n;
 145 }
 146
 147 static int perf_open(struct inode *inode, struct file *file)
 148 {
 149         struct msm_perf_state *perf = inode->i_private;
 150         struct drm_device *dev = perf->dev;
 151         struct msm_drm_private *priv = dev->dev_private;
 152         struct msm_gpu *gpu = priv->gpu;
 153         int ret = 0;
 154
 155         mutex_lock(&dev->struct_mutex);
 156
 157         if (perf->open || !gpu) {
 158                 ret = -EBUSY;
 159                 goto out;
 160         }
 161
 162         file->private_data = perf;
 163         perf->open = true;
 164         perf->cnt = 0;
 165         perf->buftot = 0;
 166         perf->bufpos = 0;
 167         msm_gpu_perfcntr_start(gpu);
 168         perf->next_jiffies = jiffies + SAMPLE_TIME;
 169
 170 out:
 171         mutex_unlock(&dev->struct_mutex);
 172         return ret;
 173 }
 174
 175 static int perf_release(struct inode *inode, struct file *file)
 176 {
 177         struct msm_perf_state *perf = inode->i_private;
 178         struct msm_drm_private *priv = perf->dev->dev_private;
 179         msm_gpu_perfcntr_stop(priv->gpu);
 180         perf->open = false;
 181         return 0;
 182 }
 183
 184
 185 static const struct file_operations perf_debugfs_fops = {
 186         .owner = THIS_MODULE,
 187         .open = perf_open,
 188         .read = perf_read,
 189         .llseek = no_llseek,
 190         .release = perf_release,
 191 };
 192
 193 int msm_perf_debugfs_init(struct drm_minor *minor)
 194 {
 195         struct msm_drm_private *priv = minor->dev->dev_private;
 196         struct msm_perf_state *perf;
 197
 198         /* only create on first minor: */
 199         if (priv->perf)
 200                 return 0;
 201
 202         perf = kzalloc(sizeof(*perf), GFP_KERNEL);
 203         if (!perf)
 204                 return -ENOMEM;
 205
 206         perf->dev = minor->dev;
 207
 208         mutex_init(&perf->read_lock);
 209         priv->perf = perf;
 210
 211         debugfs_create_file("perf", S_IFREG | S_IRUGO, minor->debugfs_root,
 212                             perf, &perf_debugfs_fops);
 213         return 0;
 214 }
 215
 216 void msm_perf_debugfs_cleanup(struct msm_drm_private *priv)
 217 {
 218         struct msm_perf_state *perf = priv->perf;
 219
 220         if (!perf)
 221                 return;
 222
 223         priv->perf = NULL;
 224
 225         mutex_destroy(&perf->read_lock);
 226
 227         kfree(perf);
 228 }
 229
 230 #endif