From: Damien Lespiau <damien.lespiau@intel.com>
To: intel-gfx@lists.freedesktop.org
Subject: [PATCH i-g-t 4/5] stats: Add a way to retrieve the standard deviation
Date: Fri, 26 Jun 2015 00:26:58 +0100 [thread overview]
Message-ID: <1435274819-2777-4-git-send-email-damien.lespiau@intel.com> (raw)
In-Reply-To: <1435274819-2777-1-git-send-email-damien.lespiau@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
---
lib/igt_stats.c | 9 +++++++++
lib/igt_stats.h | 1 +
lib/tests/Makefile.am | 2 +-
lib/tests/igt_stats.c | 33 +++++++++++++++++++++++++++++++++
tools/Makefile.am | 2 +-
tools/quick_dump/Makefile.am | 1 +
6 files changed, 46 insertions(+), 2 deletions(-)
diff --git a/lib/igt_stats.c b/lib/igt_stats.c
index 20db806..65c0ac6 100644
--- a/lib/igt_stats.c
+++ b/lib/igt_stats.c
@@ -22,6 +22,8 @@
*
*/
+#include <math.h>
+
#include "igt_core.h"
#include "igt_stats.h"
@@ -86,3 +88,10 @@ double igt_stats_get_variance(igt_stats_t *stats)
return stats->variance;
}
+
+double igt_stats_get_std_deviation(igt_stats_t *stats)
+{
+ igt_stats_knuth_mean_variance(stats);
+
+ return sqrt(stats->variance);
+}
diff --git a/lib/igt_stats.h b/lib/igt_stats.h
index acb86a6..371def3 100644
--- a/lib/igt_stats.h
+++ b/lib/igt_stats.h
@@ -37,3 +37,4 @@ void igt_stats_fini(igt_stats_t *stats);
void igt_stats_push(igt_stats_t *stats, uint64_t value);
double igt_stats_get_mean(igt_stats_t *stats);
double igt_stats_get_variance(igt_stats_t *stats);
+double igt_stats_get_std_deviation(igt_stats_t *stats);
diff --git a/lib/tests/Makefile.am b/lib/tests/Makefile.am
index e59065b..938d2ab 100644
--- a/lib/tests/Makefile.am
+++ b/lib/tests/Makefile.am
@@ -15,5 +15,5 @@ AM_CFLAGS = $(DRM_CFLAGS) $(CWARNFLAGS) \
LDADD = ../libintel_tools.la $(PCIACCESS_LIBS) $(DRM_LIBS) $(LIBUNWIND_LIBS)
-LDADD += $(CAIRO_LIBS) $(LIBUDEV_LIBS) $(GLIB_LIBS)
+LDADD += $(CAIRO_LIBS) $(LIBUDEV_LIBS) $(GLIB_LIBS) -lm
AM_CFLAGS += $(CAIRO_CFLAGS) $(LIBUDEV_CFLAGS) $(GLIB_CFLAGS)
diff --git a/lib/tests/igt_stats.c b/lib/tests/igt_stats.c
index c20b453..172e4b3 100644
--- a/lib/tests/igt_stats.c
+++ b/lib/tests/igt_stats.c
@@ -45,7 +45,40 @@ static void test_mean(void)
igt_stats_fini(&stats);
}
+/*
+ * Taken from the "Basic examples" section of:
+ * https://en.wikipedia.org/wiki/Standard_deviation
+ */
+static void test_std_deviation(void)
+{
+ igt_stats_t stats;
+ double mean, variance, std_deviation;
+
+ igt_stats_init(&stats, 8);
+
+ igt_stats_push(&stats, 2);
+ igt_stats_push(&stats, 4);
+ igt_stats_push(&stats, 4);
+ igt_stats_push(&stats, 4);
+ igt_stats_push(&stats, 5);
+ igt_stats_push(&stats, 5);
+ igt_stats_push(&stats, 7);
+ igt_stats_push(&stats, 9);
+
+ mean = igt_stats_get_mean(&stats);
+ igt_assert(mean == (2 + 3 * 4 + 2 * 5 + 7 + 9) / 8.);
+
+ variance = igt_stats_get_variance(&stats);
+ igt_assert(variance == 4);
+
+ std_deviation = igt_stats_get_std_deviation(&stats);
+ igt_assert(std_deviation == 2);
+
+ igt_stats_fini(&stats);
+}
+
igt_simple_main
{
test_mean();
+ test_std_deviation();
}
diff --git a/tools/Makefile.am b/tools/Makefile.am
index 04bfd12..8288248 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -8,5 +8,5 @@ endif
AM_CPPFLAGS = -I$(top_srcdir) -I$(top_srcdir)/lib
AM_CFLAGS = $(DRM_CFLAGS) $(PCIACCESS_CFLAGS) $(CWARNFLAGS) $(CAIRO_CFLAGS) $(LIBUNWIND_CFLAGS)
-LDADD = $(top_builddir)/lib/libintel_tools.la $(DRM_LIBS) $(PCIACCESS_LIBS) $(CAIRO_LIBS) $(LIBUDEV_LIBS) $(LIBUNWIND_LIBS)
+LDADD = $(top_builddir)/lib/libintel_tools.la $(DRM_LIBS) $(PCIACCESS_LIBS) $(CAIRO_LIBS) $(LIBUDEV_LIBS) $(LIBUNWIND_LIBS) -lm
diff --git a/tools/quick_dump/Makefile.am b/tools/quick_dump/Makefile.am
index 3d0bd23..0643a81 100644
--- a/tools/quick_dump/Makefile.am
+++ b/tools/quick_dump/Makefile.am
@@ -15,6 +15,7 @@ I915ChipsetPython_la_LIBADD = \
$(CAIRO_LIBS) \
$(LIBUNWIND_LIBS) \
-lrt \
+ -lm \
$(NULL)
chipset.py: chipset_wrap_python.c
--
2.1.0
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next prev parent reply other threads:[~2015-06-25 23:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-25 23:26 [PATCH i-g-t 1/5] stats: Be more precise and talk about mean, not average Damien Lespiau
2015-06-25 23:26 ` [PATCH i-g-t 2/5] tests/igt_stats: Call igt_stats_fini() to not leak the array Damien Lespiau
2015-06-26 9:58 ` Chris Wilson
2015-06-25 23:26 ` [PATCH i-g-t 3/5] stats: Use an algorithm popularised by Knuth to compute mean and variance Damien Lespiau
2015-06-25 23:26 ` Damien Lespiau [this message]
2015-06-25 23:26 ` [PATCH i-g-t 5/5] tests/stats: Make sure we properly invalidate the cached mean Damien Lespiau
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