On Thu, 04 Jun 2015 10:35:17 +0300 Pavel Fedin <p.fe...@samsung.com> wrote:
> Hello Luiz! Have you missed this ? Well, this is a QOM patch. QOM also has an object abstraction, but it's not the same as QObject. I'm CC'ing the maintainer. > > 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 > > > >