Mesa (main): intel/perf: deal with OA reports timestamp values on DG2

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Module: Mesa
Branch: main
Commit: 9d0db8d4c487efcc722cf77a6304168125234c34
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=9d0db8d4c487efcc722cf77a6304168125234c34

Author: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Date:   Wed Jun 23 19:17:51 2021 +0300

intel/perf: deal with OA reports timestamp values on DG2

OA reports on XeHP have their timestamp shifted to the left by 1. To
get that back in the same time domain as the REG_READ you need to
shift it back to the right and you're loosing the top bit.

v2: use ull for 64bit constant (Ian)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16144>

---

 src/intel/ds/intel_pps_driver.cc |  7 ++++---
 src/intel/perf/intel_perf.c      |  9 ++++++++-
 src/intel/perf/intel_perf.h      | 12 ++++++++++++
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/intel/ds/intel_pps_driver.cc b/src/intel/ds/intel_pps_driver.cc
index 81a46252e2f..c54aaca643e 100644
--- a/src/intel/ds/intel_pps_driver.cc
+++ b/src/intel/ds/intel_pps_driver.cc
@@ -161,6 +161,7 @@ void IntelDriver::enable_perfcnt(uint64_t sampling_period_ns)
 {
    this->sampling_period_ns = sampling_period_ns;
 
+   gpu_timestamp_udw = intel_read_gpu_timestamp(drm_device.fd) & ~perf->cfg->oa_timestamp_mask;
    if (!perf->open(sampling_period_ns, selected_query)) {
       PPS_LOG_FATAL("Failed to open intel perf");
    }
@@ -212,10 +213,10 @@ std::vector<PerfRecord> IntelDriver::parse_perf_records(const std::vector<uint8_
           * do it now. If we see a roll over the lower 32bits capture it
           * again.
           */
-         if (gpu_timestamp_udw == 0 || (gpu_timestamp_udw + gpu_timestamp_ldw) < last_gpu_timestamp)
-            gpu_timestamp_udw = intel_read_gpu_timestamp(drm_device.fd) & 0xffffffff00000000;
+         if (gpu_timestamp_udw == 0 || (gpu_timestamp_udw | gpu_timestamp_ldw) < last_gpu_timestamp)
+            gpu_timestamp_udw = intel_read_gpu_timestamp(drm_device.fd) & ~perf->cfg->oa_timestamp_mask;
 
-         uint64_t gpu_timestamp = gpu_timestamp_udw + gpu_timestamp_ldw;
+         uint64_t gpu_timestamp = gpu_timestamp_udw | gpu_timestamp_ldw;
 
          auto duration = intel_device_info_timebase_scale(&perf->devinfo,
                                                           gpu_timestamp - prev_gpu_timestamp);
diff --git a/src/intel/perf/intel_perf.c b/src/intel/perf/intel_perf.c
index 88ab9595846..a5ed622439f 100644
--- a/src/intel/perf/intel_perf.c
+++ b/src/intel/perf/intel_perf.c
@@ -714,6 +714,13 @@ oa_metrics_available(struct intel_perf_config *perf, int fd,
    perf->i915_query_supported = i915_query_perf_config_supported(perf, fd);
    perf->i915_perf_version = i915_perf_version(fd);
 
+   /* TODO: We should query this from i915 */
+   if (intel_device_info_is_dg2(devinfo))
+      perf->oa_timestamp_shift = 1;
+
+   perf->oa_timestamp_mask =
+      0xffffffffffffffffull >> (32 + perf->oa_timestamp_shift);
+
    /* Record the default SSEU configuration. */
    i915_get_sseu(fd, &perf->sseu);
 
@@ -1042,7 +1049,7 @@ uint64_t
 intel_perf_report_timestamp(const struct intel_perf_query_info *query,
                             const uint32_t *report)
 {
-   return report[1];
+   return report[1] >> query->perf->oa_timestamp_shift;
 }
 
 void
diff --git a/src/intel/perf/intel_perf.h b/src/intel/perf/intel_perf.h
index 6f26041c443..bb809a42afc 100644
--- a/src/intel/perf/intel_perf.h
+++ b/src/intel/perf/intel_perf.h
@@ -326,6 +326,18 @@ struct intel_perf_config {
    /* Version of the i915-perf subsystem, refer to i915_drm.h. */
    int i915_perf_version;
 
+   /* Number of bits to shift the OA timestamp values by to match the ring
+    * timestamp.
+    */
+   int oa_timestamp_shift;
+
+   /* Mask of bits valid from the OA report (for instance you might have the
+    * lower 31 bits [30:0] of timestamp value). This is useful if you want to
+    * recombine a full timestamp value captured from the CPU with OA
+    * timestamps captured on the device but that only include 31bits of data.
+    */
+   uint64_t oa_timestamp_mask;
+
    /* Powergating configuration for the running the query. */
    struct drm_i915_gem_context_param_sseu sseu;