Hi Robert,
I think I've spotted one interesting, yet trivial bit.
On 14 September 2016 at 15:19, Robert Bragg <robert@xxxxxxxxxxxxx> wrote:
> Adds base i915 perf infrastructure for Gen performance metrics.
>
> This adds a DRM_IOCTL_I915_PERF_OPEN ioctl that takes an array of uint64
> properties to configure a stream of metrics and returns a new fd usable
> with standard VFS system calls including read() to read typed and sized
> records; ioctl() to enable or disable capture and poll() to wait for
> data.
>
> A stream is opened something like:
>
> uint64_t properties[] = {
> /* Single context sampling */
> DRM_I915_PERF_PROP_CTX_HANDLE, ctx_handle,
>
> /* Include OA reports in samples */
> DRM_I915_PERF_PROP_SAMPLE_OA, true,
>
> /* OA unit configuration */
> DRM_I915_PERF_PROP_OA_METRICS_SET, metrics_set_id,
> DRM_I915_PERF_PROP_OA_FORMAT, report_format,
> DRM_I915_PERF_PROP_OA_EXPONENT, period_exponent,
> };
> struct drm_i915_perf_open_param parm = {
> .flags = I915_PERF_FLAG_FD_CLOEXEC |
> I915_PERF_FLAG_FD_NONBLOCK |
> I915_PERF_FLAG_DISABLED,
> .properties_ptr = (uint64_t)properties,
> .num_properties = sizeof(properties) / 16,
> };
> int fd = drmIoctl(drm_fd, DRM_IOCTL_I915_PERF_OPEN, ¶m);
>
> Records read all start with a common { type, size } header with
> DRM_I915_PERF_RECORD_SAMPLE being of most interest. Sample records
> contain an extensible number of fields and it's the
> DRM_I915_PERF_PROP_SAMPLE_xyz properties given when opening that
> determine what's included in every sample.
>
If I'm understanding the above correctly the ioctl can only read user
data and does not write to params, correct ?
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> +#define DRM_IOCTL_I915_PERF_OPEN DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_PERF_OPEN, struct drm_i915_perf_open_param)
If so, we seems to have a one letter too much in DRM_IOWR - should one
use DRM_IOW/DRM_IOR ? Then again I'm not sure how many ioctls bother,
so please don't read too much into my suggestion :-)
Regards,
Emil
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