Quoting Lionel Landwerlin (2019-02-04 17:30:12) > On 22/01/2019 16:25, Joonas Lahtinen wrote: > > Quoting Lionel Landwerlin (2019-01-16 17:36:22) > >> With the currently available parameters for the i915-perf stream, > >> there are still situations that are not well covered : > >> > >> If an application opens the stream with polling disable or at very low > >> frequency and OA interrupt enabled, no data will be available even > >> though somewhere between nothing and half of the OA buffer worth of > >> data might have landed in memory. > >> > >> To solve this issue we have a new flush ioctl on the perf stream that > >> forces the i915-perf driver to look at the state of the buffer when > >> called and makes any data available through both poll() & read() type > >> syscalls. > >> > >> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx> > > Link to userspace changes? > > > > Regards, Joonas > > > Hey Joonas, > > > I'm about to make the changes in gputop for the high frequency sampling > use case. > > > One thing I would like to know is whether these new features should be > reported through a flag. > > So far we haven't added any new option to the i915/perf driver since the > initial upstreaming series. > > > The way I'm currently detecting newly added parameters is by using > trying to open the stream with a value that I know will report ENOENT > rather than EINVAL when the feature is not available : > > https://github.com/djdeath/intel-gpu-tools/blob/wip/djdeath/oa-interrupts/tests/perf.c#L4345 > > Is there a better way to do this? I think I already responded in IRC, but here goes for e-mail archives. A GETPARAM with rolling i915/perf version would probably be a justified versioning interface. Regards, Joonas > > > Thanks, > > > -Lionel > > > > > >> --- > >> drivers/gpu/drm/i915/i915_perf.c | 17 +++++++++++++++++ > >> include/uapi/drm/i915_drm.h | 19 +++++++++++++++++++ > >> 2 files changed, 36 insertions(+) > >> > >> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c > >> index da721fce2543..6c98ffa2135e 100644 > >> --- a/drivers/gpu/drm/i915/i915_perf.c > >> +++ b/drivers/gpu/drm/i915/i915_perf.c > >> @@ -2433,6 +2433,20 @@ static void i915_perf_disable_locked(struct i915_perf_stream *stream) > >> stream->ops->disable(stream); > >> } > >> > >> +/** > >> + * i915_perf_flush_data - handle `I915_PERF_IOCTL_FLUSH_DATA` ioctl > >> + * @stream: An enabled i915 perf stream > >> + * > >> + * The intention is to flush all the data available for reading from the OA > >> + * buffer > >> + */ > >> +static void i915_perf_flush_data(struct i915_perf_stream *stream) > >> +{ > >> + struct drm_i915_private *dev_priv = stream->dev_priv; > >> + > >> + dev_priv->perf.oa.pollin = oa_buffer_check(stream->dev_priv, true); > >> +} > >> + > >> /** > >> * i915_perf_ioctl - support ioctl() usage with i915 perf stream FDs > >> * @stream: An i915 perf stream > >> @@ -2456,6 +2470,9 @@ static long i915_perf_ioctl_locked(struct i915_perf_stream *stream, > >> case I915_PERF_IOCTL_DISABLE: > >> i915_perf_disable_locked(stream); > >> return 0; > >> + case I915_PERF_IOCTL_FLUSH_DATA: > >> + i915_perf_flush_data(stream); > >> + return 0; > >> } > >> > >> return -EINVAL; > >> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h > >> index b6db5e544a35..0f0d20080572 100644 > >> --- a/include/uapi/drm/i915_drm.h > >> +++ b/include/uapi/drm/i915_drm.h > >> @@ -1594,6 +1594,25 @@ struct drm_i915_perf_open_param { > >> */ > >> #define I915_PERF_IOCTL_DISABLE _IO('i', 0x1) > >> > >> +/** > >> + * Actively check the availability of data from a stream. > >> + * > >> + * A stream data availability can be driven by two types of events : > >> + * > >> + * - if enabled, the kernel's hrtimer checking the amount of available data > >> + * in the OA buffer through head/tail registers. > >> + * > >> + * - if enabled, the OA unit's interrupt mechanism > >> + * > >> + * The kernel hrtimer incur a cost of running callback at fixed time > >> + * intervals, while the OA interrupt might only happen rarely. In the > >> + * situation where the application has disabled the kernel's hrtimer and only > >> + * uses the OA interrupt to know about available data, the application can > >> + * request an active check of the available OA data through this ioctl. This > >> + * will make any data in the OA buffer available with either poll() or read(). > >> + */ > >> +#define I915_PERF_IOCTL_FLUSH_DATA _IO('i', 0x2) > >> + > >> /** > >> * Common to all i915 perf records > >> */ > >> -- > >> 2.20.1 > >> > >> _______________________________________________ > >> Intel-gfx mailing list > >> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > >> https://lists.freedesktop.org/mailman/listinfo/intel-gfx > > _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
