linux/drivers/gpu/drm/msm/msm_perf.c
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   1/*
   2 * Copyright (C) 2013 Red Hat
   3 * Author: Rob Clark <robdclark@gmail.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify it
   6 * under the terms of the GNU General Public License version 2 as published by
   7 * the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it will be useful, but WITHOUT
  10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12 * more details.
  13 *
  14 * You should have received a copy of the GNU General Public License along with
  15 * this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18/* For profiling, userspace can:
  19 *
  20 *   tail -f /sys/kernel/debug/dri/<minor>/gpu
  21 *
  22 * This will enable performance counters/profiling to track the busy time
  23 * and any gpu specific performance counters that are supported.
  24 */
  25
  26#ifdef CONFIG_DEBUG_FS
  27
  28#include <linux/debugfs.h>
  29
  30#include "msm_drv.h"
  31#include "msm_gpu.h"
  32
  33struct msm_perf_state {
  34        struct drm_device *dev;
  35
  36        bool open;
  37        int cnt;
  38        struct mutex read_lock;
  39
  40        char buf[256];
  41        int buftot, bufpos;
  42
  43        unsigned long next_jiffies;
  44
  45        struct dentry *ent;
  46        struct drm_info_node *node;
  47};
  48
  49#define SAMPLE_TIME (HZ/4)
  50
  51/* wait for next sample time: */
  52static int wait_sample(struct msm_perf_state *perf)
  53{
  54        unsigned long start_jiffies = jiffies;
  55
  56        if (time_after(perf->next_jiffies, start_jiffies)) {
  57                unsigned long remaining_jiffies =
  58                        perf->next_jiffies - start_jiffies;
  59                int ret = schedule_timeout_interruptible(remaining_jiffies);
  60                if (ret > 0) {
  61                        /* interrupted */
  62                        return -ERESTARTSYS;
  63                }
  64        }
  65        perf->next_jiffies += SAMPLE_TIME;
  66        return 0;
  67}
  68
  69static int refill_buf(struct msm_perf_state *perf)
  70{
  71        struct msm_drm_private *priv = perf->dev->dev_private;
  72        struct msm_gpu *gpu = priv->gpu;
  73        char *ptr = perf->buf;
  74        int rem = sizeof(perf->buf);
  75        int i, n;
  76
  77        if ((perf->cnt++ % 32) == 0) {
  78                /* Header line: */
  79                n = snprintf(ptr, rem, "%%BUSY");
  80                ptr += n;
  81                rem -= n;
  82
  83                for (i = 0; i < gpu->num_perfcntrs; i++) {
  84                        const struct msm_gpu_perfcntr *perfcntr = &gpu->perfcntrs[i];
  85                        n = snprintf(ptr, rem, "\t%s", perfcntr->name);
  86                        ptr += n;
  87                        rem -= n;
  88                }
  89        } else {
  90                /* Sample line: */
  91                uint32_t activetime = 0, totaltime = 0;
  92                uint32_t cntrs[5];
  93                uint32_t val;
  94                int ret;
  95
  96                /* sleep until next sample time: */
  97                ret = wait_sample(perf);
  98                if (ret)
  99                        return ret;
 100
 101                ret = msm_gpu_perfcntr_sample(gpu, &activetime, &totaltime,
 102                                ARRAY_SIZE(cntrs), cntrs);
 103                if (ret < 0)
 104                        return ret;
 105
 106                val = totaltime ? 1000 * activetime / totaltime : 0;
 107                n = snprintf(ptr, rem, "%3d.%d%%", val / 10, val % 10);
 108                ptr += n;
 109                rem -= n;
 110
 111                for (i = 0; i < ret; i++) {
 112                        /* cycle counters (I think).. convert to MHz.. */
 113                        val = cntrs[i] / 10000;
 114                        n = snprintf(ptr, rem, "\t%5d.%02d",
 115                                        val / 100, val % 100);
 116                        ptr += n;
 117                        rem -= n;
 118                }
 119        }
 120
 121        n = snprintf(ptr, rem, "\n");
 122        ptr += n;
 123        rem -= n;
 124
 125        perf->bufpos = 0;
 126        perf->buftot = ptr - perf->buf;
 127
 128        return 0;
 129}
 130
 131static ssize_t perf_read(struct file *file, char __user *buf,
 132                size_t sz, loff_t *ppos)
 133{
 134        struct msm_perf_state *perf = file->private_data;
 135        int n = 0, ret = 0;
 136
 137        mutex_lock(&perf->read_lock);
 138
 139        if (perf->bufpos >= perf->buftot) {
 140                ret = refill_buf(perf);
 141                if (ret)
 142                        goto out;
 143        }
 144
 145        n = min((int)sz, perf->buftot - perf->bufpos);
 146        if (copy_to_user(buf, &perf->buf[perf->bufpos], n)) {
 147                ret = -EFAULT;
 148                goto out;
 149        }
 150
 151        perf->bufpos += n;
 152        *ppos += n;
 153
 154out:
 155        mutex_unlock(&perf->read_lock);
 156        if (ret)
 157                return ret;
 158        return n;
 159}
 160
 161static int perf_open(struct inode *inode, struct file *file)
 162{
 163        struct msm_perf_state *perf = inode->i_private;
 164        struct drm_device *dev = perf->dev;
 165        struct msm_drm_private *priv = dev->dev_private;
 166        struct msm_gpu *gpu = priv->gpu;
 167        int ret = 0;
 168
 169        mutex_lock(&dev->struct_mutex);
 170
 171        if (perf->open || !gpu) {
 172                ret = -EBUSY;
 173                goto out;
 174        }
 175
 176        file->private_data = perf;
 177        perf->open = true;
 178        perf->cnt = 0;
 179        perf->buftot = 0;
 180        perf->bufpos = 0;
 181        msm_gpu_perfcntr_start(gpu);
 182        perf->next_jiffies = jiffies + SAMPLE_TIME;
 183
 184out:
 185        mutex_unlock(&dev->struct_mutex);
 186        return ret;
 187}
 188
 189static int perf_release(struct inode *inode, struct file *file)
 190{
 191        struct msm_perf_state *perf = inode->i_private;
 192        struct msm_drm_private *priv = perf->dev->dev_private;
 193        msm_gpu_perfcntr_stop(priv->gpu);
 194        perf->open = false;
 195        return 0;
 196}
 197
 198
 199static const struct file_operations perf_debugfs_fops = {
 200        .owner = THIS_MODULE,
 201        .open = perf_open,
 202        .read = perf_read,
 203        .llseek = no_llseek,
 204        .release = perf_release,
 205};
 206
 207int msm_perf_debugfs_init(struct drm_minor *minor)
 208{
 209        struct msm_drm_private *priv = minor->dev->dev_private;
 210        struct msm_perf_state *perf;
 211
 212        /* only create on first minor: */
 213        if (priv->perf)
 214                return 0;
 215
 216        perf = kzalloc(sizeof(*perf), GFP_KERNEL);
 217        if (!perf)
 218                return -ENOMEM;
 219
 220        perf->dev = minor->dev;
 221
 222        mutex_init(&perf->read_lock);
 223        priv->perf = perf;
 224
 225        perf->node = kzalloc(sizeof(*perf->node), GFP_KERNEL);
 226        if (!perf->node)
 227                goto fail;
 228
 229        perf->ent = debugfs_create_file("perf", S_IFREG | S_IRUGO,
 230                        minor->debugfs_root, perf, &perf_debugfs_fops);
 231        if (!perf->ent) {
 232                DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/perf\n",
 233                                minor->debugfs_root);
 234                goto fail;
 235        }
 236
 237        perf->node->minor = minor;
 238        perf->node->dent  = perf->ent;
 239        perf->node->info_ent = NULL;
 240
 241        mutex_lock(&minor->debugfs_lock);
 242        list_add(&perf->node->list, &minor->debugfs_list);
 243        mutex_unlock(&minor->debugfs_lock);
 244
 245        return 0;
 246
 247fail:
 248        msm_perf_debugfs_cleanup(minor);
 249        return -1;
 250}
 251
 252void msm_perf_debugfs_cleanup(struct drm_minor *minor)
 253{
 254        struct msm_drm_private *priv = minor->dev->dev_private;
 255        struct msm_perf_state *perf = priv->perf;
 256
 257        if (!perf)
 258                return;
 259
 260        priv->perf = NULL;
 261
 262        debugfs_remove(perf->ent);
 263
 264        if (perf->node) {
 265                mutex_lock(&minor->debugfs_lock);
 266                list_del(&perf->node->list);
 267                mutex_unlock(&minor->debugfs_lock);
 268                kfree(perf->node);
 269        }
 270
 271        mutex_destroy(&perf->read_lock);
 272
 273        kfree(perf);
 274}
 275
 276#endif
 277