1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2013 Red Hat 4 * Author: Rob Clark <robdclark@gmail.com> 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 #include <linux/uaccess.h> 19 20 #include <drm/drm_file.h> 21 22 #include "msm_drv.h" 23 #include "msm_gpu.h" 24 25 struct msm_perf_state { 26 struct drm_device *dev; 27 28 bool open; 29 int cnt; 30 struct mutex read_lock; 31 32 char buf[256]; 33 int buftot, bufpos; 34 35 unsigned long next_jiffies; 36 }; 37 38 #define SAMPLE_TIME (HZ/4) 39 40 /* wait for next sample time: */ 41 static int wait_sample(struct msm_perf_state *perf) 42 { 43 unsigned long start_jiffies = jiffies; 44 45 if (time_after(perf->next_jiffies, start_jiffies)) { 46 unsigned long remaining_jiffies = 47 perf->next_jiffies - start_jiffies; 48 int ret = schedule_timeout_interruptible(remaining_jiffies); 49 if (ret > 0) { 50 /* interrupted */ 51 return -ERESTARTSYS; 52 } 53 } 54 perf->next_jiffies += SAMPLE_TIME; 55 return 0; 56 } 57 58 static int refill_buf(struct msm_perf_state *perf) 59 { 60 struct msm_drm_private *priv = perf->dev->dev_private; 61 struct msm_gpu *gpu = priv->gpu; 62 char *ptr = perf->buf; 63 int rem = sizeof(perf->buf); 64 int i, n; 65 66 if ((perf->cnt++ % 32) == 0) { 67 /* Header line: */ 68 n = snprintf(ptr, rem, "%%BUSY"); 69 ptr += n; 70 rem -= n; 71 72 for (i = 0; i < gpu->num_perfcntrs; i++) { 73 const struct msm_gpu_perfcntr *perfcntr = &gpu->perfcntrs[i]; 74 n = snprintf(ptr, rem, "\t%s", perfcntr->name); 75 ptr += n; 76 rem -= n; 77 } 78 } else { 79 /* Sample line: */ 80 uint32_t activetime = 0, totaltime = 0; 81 uint32_t cntrs[5]; 82 uint32_t val; 83 int ret; 84 85 /* sleep until next sample time: */ 86 ret = wait_sample(perf); 87 if (ret) 88 return ret; 89 90 ret = msm_gpu_perfcntr_sample(gpu, &activetime, &totaltime, 91 ARRAY_SIZE(cntrs), cntrs); 92 if (ret < 0) 93 return ret; 94 95 val = totaltime ? 1000 * activetime / totaltime : 0; 96 n = snprintf(ptr, rem, "%3d.%d%%", val / 10, val % 10); 97 ptr += n; 98 rem -= n; 99 100 for (i = 0; i < ret; i++) { 101 /* cycle counters (I think).. convert to MHz.. */ 102 val = cntrs[i] / 10000; 103 n = snprintf(ptr, rem, "\t%5d.%02d", 104 val / 100, val % 100); 105 ptr += n; 106 rem -= n; 107 } 108 } 109 110 n = snprintf(ptr, rem, "\n"); 111 ptr += n; 112 rem -= n; 113 114 perf->bufpos = 0; 115 perf->buftot = ptr - perf->buf; 116 117 return 0; 118 } 119 120 static ssize_t perf_read(struct file *file, char __user *buf, 121 size_t sz, loff_t *ppos) 122 { 123 struct msm_perf_state *perf = file->private_data; 124 int n = 0, ret = 0; 125 126 mutex_lock(&perf->read_lock); 127 128 if (perf->bufpos >= perf->buftot) { 129 ret = refill_buf(perf); 130 if (ret) 131 goto out; 132 } 133 134 n = min((int)sz, perf->buftot - perf->bufpos); 135 if (copy_to_user(buf, &perf->buf[perf->bufpos], n)) { 136 ret = -EFAULT; 137 goto out; 138 } 139 140 perf->bufpos += n; 141 *ppos += n; 142 143 out: 144 mutex_unlock(&perf->read_lock); 145 if (ret) 146 return ret; 147 return n; 148 } 149 150 static int perf_open(struct inode *inode, struct file *file) 151 { 152 struct msm_perf_state *perf = inode->i_private; 153 struct drm_device *dev = perf->dev; 154 struct msm_drm_private *priv = dev->dev_private; 155 struct msm_gpu *gpu = priv->gpu; 156 int ret = 0; 157 158 mutex_lock(&dev->struct_mutex); 159 160 if (perf->open || !gpu) { 161 ret = -EBUSY; 162 goto out; 163 } 164 165 file->private_data = perf; 166 perf->open = true; 167 perf->cnt = 0; 168 perf->buftot = 0; 169 perf->bufpos = 0; 170 msm_gpu_perfcntr_start(gpu); 171 perf->next_jiffies = jiffies + SAMPLE_TIME; 172 173 out: 174 mutex_unlock(&dev->struct_mutex); 175 return ret; 176 } 177 178 static int perf_release(struct inode *inode, struct file *file) 179 { 180 struct msm_perf_state *perf = inode->i_private; 181 struct msm_drm_private *priv = perf->dev->dev_private; 182 msm_gpu_perfcntr_stop(priv->gpu); 183 perf->open = false; 184 return 0; 185 } 186 187 188 static const struct file_operations perf_debugfs_fops = { 189 .owner = THIS_MODULE, 190 .open = perf_open, 191 .read = perf_read, 192 .llseek = no_llseek, 193 .release = perf_release, 194 }; 195 196 int msm_perf_debugfs_init(struct drm_minor *minor) 197 { 198 struct msm_drm_private *priv = minor->dev->dev_private; 199 struct msm_perf_state *perf; 200 201 /* only create on first minor: */ 202 if (priv->perf) 203 return 0; 204 205 perf = kzalloc(sizeof(*perf), GFP_KERNEL); 206 if (!perf) 207 return -ENOMEM; 208 209 perf->dev = minor->dev; 210 211 mutex_init(&perf->read_lock); 212 priv->perf = perf; 213 214 debugfs_create_file("perf", S_IFREG | S_IRUGO, minor->debugfs_root, 215 perf, &perf_debugfs_fops); 216 return 0; 217 } 218 219 void msm_perf_debugfs_cleanup(struct msm_drm_private *priv) 220 { 221 struct msm_perf_state *perf = priv->perf; 222 223 if (!perf) 224 return; 225 226 priv->perf = NULL; 227 228 mutex_destroy(&perf->read_lock); 229 230 kfree(perf); 231 } 232 233 #endif 234