Re: [PATCH 32/83] hsa/radeon: implementing IOCTL for clock counters

On Fri, Jul 11, 2014 at 12:53:48AM +0300, Oded Gabbay wrote:

From: Evgeny Pinchuk evgeny.pinchuk@amd.com

Implemented new IOCTL to query the CPU and GPU clock counters.

Signed-off-by: Evgeny Pinchuk evgeny.pinchuk@amd.com Signed-off-by: Oded Gabbay oded.gabbay@amd.com

---

drivers/gpu/hsa/radeon/kfd_chardev.c | 37 ++++++++++++++++++++++++++++++++++++ include/uapi/linux/kfd_ioctl.h | 9 +++++++++ 2 files changed, 46 insertions(+)

diff --git a/drivers/gpu/hsa/radeon/kfd_chardev.c b/drivers/gpu/hsa/radeon/kfd_chardev.c index ddaf357..d6fa980 100644 --- a/drivers/gpu/hsa/radeon/kfd_chardev.c +++ b/drivers/gpu/hsa/radeon/kfd_chardev.c @@ -28,6 +28,7 @@ #include <linux/slab.h> #include <linux/uaccess.h> #include <uapi/linux/kfd_ioctl.h> +#include <linux/time.h> #include "kfd_priv.h" #include "kfd_scheduler.h"

@@ -284,6 +285,38 @@ out: return err; }

+static long +kfd_ioctl_get_clock_counters(struct file *filep, struct kfd_process *p, void __user *arg) +{

• struct kfd_ioctl_get_clock_counters_args args;
• struct kfd_dev *dev;
• struct timespec time;
• if (copy_from_user(&args, arg, sizeof(args)))

• return -EFAULT;
  

• dev = radeon_kfd_device_by_id(args.gpu_id);
• if (dev == NULL)

• return -EINVAL;
  

• /* Reading GPU clock counter from KGD */
• args.gpu_clock_counter = kfd2kgd->get_gpu_clock_counter(dev->kgd);
• /* No access to rdtsc. Using raw monotonic time */
• getrawmonotonic(&time);
• args.cpu_clock_counter = time.tv_nsec;

Is the GPU clock counter monotonic too ? Even after GPU reset (hard reset included) what could go wrong if it rolls back ?

• get_monotonic_boottime(&time);
• args.system_clock_counter = time.tv_nsec;
• /* Since the counter is in nano-seconds we use 1GHz frequency */
• args.system_clock_freq = 1000000000;
• if (copy_to_user(arg, &args, sizeof(args)))

• return -EFAULT;
  

• return 0;

+}

static long kfd_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) @@ -312,6 +345,10 @@ kfd_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) err = kfd_ioctl_set_memory_policy(filep, process, (void __user *)arg); break;

• case KFD_IOC_GET_CLOCK_COUNTERS:

• err = kfd_ioctl_get_clock_counters(filep, process, (void __user *)arg);
  

• break;
  

• default: dev_err(kfd_device, "unknown ioctl cmd 0x%x, arg 0x%lx)\n",

diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h index 928e628..5b9517e 100644 --- a/include/uapi/linux/kfd_ioctl.h +++ b/include/uapi/linux/kfd_ioctl.h @@ -70,12 +70,21 @@ struct kfd_ioctl_set_memory_policy_args { uint64_t alternate_aperture_size; /* to KFD */ };

+struct kfd_ioctl_get_clock_counters_args {

• uint32_t gpu_id; /* to KFD */
• uint64_t gpu_clock_counter; /* from KFD */
• uint64_t cpu_clock_counter; /* from KFD */
• uint64_t system_clock_counter; /* from KFD */
• uint64_t system_clock_freq; /* from KFD */

+};

#define KFD_IOC_MAGIC 'K'

#define KFD_IOC_GET_VERSION _IOR(KFD_IOC_MAGIC, 1, struct kfd_ioctl_get_version_args) #define KFD_IOC_CREATE_QUEUE _IOWR(KFD_IOC_MAGIC, 2, struct kfd_ioctl_create_queue_args) #define KFD_IOC_DESTROY_QUEUE _IOWR(KFD_IOC_MAGIC, 3, struct kfd_ioctl_destroy_queue_args) #define KFD_IOC_SET_MEMORY_POLICY _IOW(KFD_IOC_MAGIC, 4, struct kfd_ioctl_set_memory_policy_args) +#define KFD_IOC_GET_CLOCK_COUNTERS _IOWR(KFD_IOC_MAGIC, 5, struct kfd_ioctl_get_clock_counters_args)

#pragma pack(pop)

-- 1.9.1