[PATCH 4/6] intel_gpu_top: initialize monitoring statistics at startup

[Eugeni Dodonov <eugeni@dodonov.net>]

From: Eugeni Dodonov <eugeni.dodonov@intel.com>

This patch initializes the last_stats[] for registers prior to starting
the monitoring itself. This way, the first measure will already contain
the difference from the previous value instead of non-initialized value.

Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
---
 tools/intel_gpu_top.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/tools/intel_gpu_top.c b/tools/intel_gpu_top.c
index edb4a82..e2dd173 100644
--- a/tools/intel_gpu_top.c
+++ b/tools/intel_gpu_top.c
@@ -475,6 +475,22 @@ int main(int argc, char **argv)
 		ring_init(&blt_ring);
 	}
 
+    /* Initialize GPU stats */
+    if (HAS_STATS_REGS(devid)) {
+        for (i = 0; i < STATS_COUNT; i++) {
+            uint32_t stats_high, stats_low, stats_high_2;
+
+            do {
+                stats_high = INREG(stats_regs[i] + 4);
+                stats_low = INREG(stats_regs[i]);
+                stats_high_2 = INREG(stats_regs[i] + 4);
+            } while (stats_high != stats_high_2);
+
+            last_stats[i] = (uint64_t)stats_high << 32 |
+                stats_low;
+        }
+    }
+
 	for (;;) {
 		int j;
 		unsigned long long t1, ti, tf;
-- 
1.7.6.1