Hello Luiz! Have you missed this ? Kind regards, Pavel Fedin Expert Engineer Samsung Electronics Research center Russia
> -----Original Message----- > From: qemu-devel-bounces+p.fedin=samsung....@nongnu.org [mailto:qemu-devel- > bounces+p.fedin=samsung....@nongnu.org] On Behalf Of Pavel Fedin > Sent: Thursday, May 28, 2015 11:42 AM > To: qemu-devel@nongnu.org > Cc: 'Luiz Capitulino' > Subject: [Qemu-devel] [PATCH] qobject: object_property_add() performance > improvement > > The function originally behaves very badly when adding properties with "[*]" > suffix. > Nomnally these are used for numbering IRQ pins. In order to find the correct > starting > number the function started from zero and checked for duplicates. This took > incredibly > long time with large number of CPUs because number of IRQ pins on some > architectures (like > ARM GICv3) gets multiplied by number of CPUs. > The solution is to add one more property which caches last used index so that duplication > check is not repeated thousands of times. Every time an array is expanded the > index is > picked up from this cache. Cache property is a uint32_t and has the original > name of the > array ('name[*]') for simplicity. > Some more improvements: > - Call object_property_add_single() instead of recursing into itself - keeps > off memcmp() > check every time when its result is already known. > - Allocate name_no_array only once and not every time for every property > (there can be > thousands of them) > The modification decreases qemu startup time with 32 ARMv8 CPUs by a factor > of 2 (~10 sec > vs ~20 sec). > > Signed-off-by: Pavel Fedin <p.fe...@samsung.com> > --- > qom/object.c | 89 > ++++++++++++++++++++++++++++++++++++++++++------------------ > 1 file changed, 62 insertions(+), 27 deletions(-) > > diff --git a/qom/object.c b/qom/object.c > index b8dff43..72480bc 100644 > --- a/qom/object.c > +++ b/qom/object.c > @@ -10,6 +10,8 @@ > * See the COPYING file in the top-level directory. > */ > > +#include <glib/gprintf.h> > + > #include "qom/object.h" > #include "qemu-common.h" > #include "qapi/visitor.h" > @@ -721,35 +723,14 @@ void object_unref(Object *obj) > } > } > > -ObjectProperty * > -object_property_add(Object *obj, const char *name, const char *type, > - ObjectPropertyAccessor *get, > - ObjectPropertyAccessor *set, > - ObjectPropertyRelease *release, > - void *opaque, Error **errp) > +static ObjectProperty * > +object_property_add_single(Object *obj, const char *name, const char *type, > + ObjectPropertyAccessor *get, > + ObjectPropertyAccessor *set, > + ObjectPropertyRelease *release, > + void *opaque, Error **errp) > { > ObjectProperty *prop; > - size_t name_len = strlen(name); > - > - if (name_len >= 3 && !memcmp(name + name_len - 3, "[*]", 4)) { > - int i; > - ObjectProperty *ret; > - char *name_no_array = g_strdup(name); > - > - name_no_array[name_len - 3] = '\0'; > - for (i = 0; ; ++i) { > - char *full_name = g_strdup_printf("%s[%d]", name_no_array, i); > - > - ret = object_property_add(obj, full_name, type, get, set, > - release, opaque, NULL); > - g_free(full_name); > - if (ret) { > - break; > - } > - } > - g_free(name_no_array); > - return ret; > - } > > QTAILQ_FOREACH(prop, &obj->properties, node) { > if (strcmp(prop->name, name) == 0) { > @@ -774,6 +755,60 @@ object_property_add(Object *obj, const char *name, const > char *type, > return prop; > } > > +static void property_get_uint32_ptr(Object *obj, Visitor *v, > + void *opaque, const char *name, > + Error **errp); > + > +ObjectProperty * > +object_property_add(Object *obj, const char *name, const char *type, > + ObjectPropertyAccessor *get, > + ObjectPropertyAccessor *set, > + ObjectPropertyRelease *release, > + void *opaque, Error **errp) > +{ > + size_t name_len = strlen(name); > + > + if (name_len >= 3 && !memcmp(name + name_len - 3, "[*]", 4)) { > + int i; > + ObjectProperty *ret, *count; > + /* 10 characters for maximum possible integer number */ > + char *name_no_array = g_malloc(name_len + 10); > + > + count = object_property_find(obj, name, NULL); > + if (count == NULL) { > + void *v = g_malloc0(sizeof(uint32_t)); > + > + /* This is the same as object_property_add_uint32_ptr(), but: > + * - Slightly faster and returns pointer > + * - Will not recurse here so that we can use > + * raw name with [*] here */ > + count = object_property_add_single(obj, name, "uint32", > + property_get_uint32_ptr, NULL, > + NULL, v, &error_abort); > + } > + > + name_len -= 2; > + memcpy(name_no_array, name, name_len); > + > + for (i = *((uint32_t *)count->opaque); ; ++i) { > + g_sprintf(&name_no_array[name_len], "%d]", i); > + > + ret = object_property_add_single(obj, name_no_array, type, get, > set, > + release, opaque, NULL); > + if (ret) { > + break; > + } > + } > + *((uint32_t *)count->opaque) = i + 1; > + > + g_free(name_no_array); > + return ret; > + } > + > + return object_property_add_single(obj, name, type, > + get, set, release, opaque, errp); > +} > + > ObjectProperty *object_property_find(Object *obj, const char *name, > Error **errp) > { > -- > 1.9.5.msysgit.0 >
