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-rw-r--r--perf/micro/hash-table.c115
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diff --git a/perf/micro/hash-table.c b/perf/micro/hash-table.c
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+/*
+ * Copyright © 2011 Andrea Canciani
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of
+ * Red Hat, Inc. not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Red Hat, Inc. makes no representations about the
+ * suitability of this software for any purpose. It is provided "as
+ * is" without express or implied warranty.
+ *
+ * RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL RED HAT, INC. BE LIABLE FOR ANY SPECIAL,
+ * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Author: Andrea Canciani <ranma42@gmail.com>
+ */
+
+#include "cairo-perf.h"
+
+#define ITER 1000
+#define HOLDOVERS 256
+#define LIVE_ENTRIES 257
+#define ACTIVE_FONTS (LIVE_ENTRIES - HOLDOVERS - 1)
+
+/*
+ * The original implementation of hash tables was very inefficient, as
+ * pointed out in https://bugs.freedesktop.org/show_bug.cgi?id=17399
+ *
+ * This benchmark tries to fill up the scaled_font_map hash table to
+ * show the O(n) behavior.
+ */
+
+static cairo_time_t
+do_hash_table (cairo_t *cr, int width, int height, int loops)
+{
+ /*
+ * Microsoft C Compiler complains that:
+ * error C2466: cannot allocate an array of constant size 0
+ * so we add an unused element to make it happy
+ */
+ cairo_scaled_font_t *active_fonts[ACTIVE_FONTS + 1];
+ cairo_matrix_t m;
+ int i;
+
+ cairo_matrix_init_identity (&m);
+
+ /* Touch HOLDOVERS scaled fonts to fill up the holdover list. */
+ for (i = 0; i < HOLDOVERS; i++) {
+ m.yy = m.xx * (i + 1);
+ cairo_set_font_matrix (cr, &m);
+ cairo_get_scaled_font (cr);
+ }
+
+ /*
+ * Reference some scaled fonts so that they will be kept in the
+ * scaled fonts map. We want LIVE_ENTRIES elements in the font
+ * map, but cairo keeps HOLDOVERS recently used fonts in it and we
+ * will be activating a new font in the cr context, so we just
+ * keep references to ACTIVE_FONTS fonts.
+ *
+ * Note: setting LIVE_ENTRIES == HOLDOVERS+1 means that we keep no
+ * font in active_fonts and the slowness is caused by the holdover
+ * fonts only.
+ */
+ for (i = 0; i < ACTIVE_FONTS; i++) {
+ cairo_scaled_font_t *scaled_font;
+
+ m.yy = m.xx * (i + 1);
+ cairo_set_font_matrix (cr, &m);
+
+ scaled_font = cairo_get_scaled_font (cr);
+ active_fonts[i] = cairo_scaled_font_reference (scaled_font);
+ }
+
+ cairo_perf_timer_start ();
+
+ while (loops--) {
+ m.xx += 1.0;
+
+ /* Generate ITER new scaled fonts per loop */
+ for (i = 0; i < ITER; i++) {
+ m.yy = m.xx * (i + 1);
+ cairo_set_font_matrix (cr, &m);
+ cairo_get_scaled_font (cr);
+ }
+ }
+
+ cairo_perf_timer_stop ();
+
+ for (i = 0; i < ACTIVE_FONTS; i++)
+ cairo_scaled_font_destroy (active_fonts[i]);
+
+ return cairo_perf_timer_elapsed ();
+}
+
+cairo_bool_t
+hash_table_enabled (cairo_perf_t *perf)
+{
+ return cairo_perf_can_run (perf, "hash-table", NULL);
+}
+
+void
+hash_table (cairo_perf_t *perf, cairo_t *cr, int width, int height)
+{
+ cairo_perf_cover_sources_and_operators (perf, "hash-table",
+ do_hash_table, NULL);
+}