xkb_x11_keymap_new_from_device: Less X11 round-trips On my system, calling xkb_x11_keymap_new_from_device() did 78 round trips to the X11 server, which seems excessive. This commit brings this number down to about 9 to 10 round trips. The existing functions adopt_atom() and adopt_atoms() guarantee that the atom was adopted by the time they return. Thus, each call to these functions must do a round-trip. However, none of the callers need this guarantee. This commit makes "atom adopting" asynchronous: Only some time later is the atom actually adopted. Until then, it is in some pending "limbo" state. This actually fixes a TODO in the comments. Fixes: https://github.com/xkbcommon/libxkbcommon/issues/216 Signed-off-by: Uli Schlachter <psychon@znc.in>
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diff --git a/src/x11/keymap.c b/src/x11/keymap.c
index f5b368f..38be217 100644
--- a/src/x11/keymap.c
+++ b/src/x11/keymap.c
@@ -852,7 +852,7 @@ fail:
}
static bool
-get_type_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
+get_type_names(struct xkb_keymap *keymap, struct x11_atom_interner *interner,
xcb_xkb_get_names_reply_t *reply,
xcb_xkb_get_names_value_list_t *list)
{
@@ -880,13 +880,9 @@ get_type_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
ALLOC_OR_FAIL(type->level_names, type->num_levels);
- if (!adopt_atom(keymap->ctx, conn, wire_type_name, &type->name))
- goto fail;
-
- if (!adopt_atoms(keymap->ctx, conn,
- kt_level_names_iter, type->level_names,
- wire_num_levels))
- goto fail;
+ x11_atom_interner_adopt_atom(interner, wire_type_name, &type->name);
+ x11_atom_interner_adopt_atoms(interner, kt_level_names_iter,
+ type->level_names, wire_num_levels);
type->num_level_names = type->num_levels;
kt_level_names_iter += wire_num_levels;
@@ -901,7 +897,8 @@ fail:
}
static bool
-get_indicator_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
+get_indicator_names(struct xkb_keymap *keymap,
+ struct x11_atom_interner *interner,
xcb_xkb_get_names_reply_t *reply,
xcb_xkb_get_names_value_list_t *list)
{
@@ -914,8 +911,7 @@ get_indicator_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
xcb_atom_t wire = *iter;
struct xkb_led *led = &keymap->leds[i];
- if (!adopt_atom(keymap->ctx, conn, wire, &led->name))
- return false;
+ x11_atom_interner_adopt_atom(interner, wire, &led->name);
iter++;
}
@@ -928,7 +924,7 @@ fail:
}
static bool
-get_vmod_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
+get_vmod_names(struct xkb_keymap *keymap, struct x11_atom_interner *interner,
xcb_xkb_get_names_reply_t *reply,
xcb_xkb_get_names_value_list_t *list)
{
@@ -947,8 +943,7 @@ get_vmod_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
xcb_atom_t wire = *iter;
struct xkb_mod *mod = &keymap->mods.mods[NUM_REAL_MODS + i];
- if (!adopt_atom(keymap->ctx, conn, wire, &mod->name))
- return false;
+ x11_atom_interner_adopt_atom(interner, wire, &mod->name);
iter++;
}
@@ -958,7 +953,7 @@ get_vmod_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
}
static bool
-get_group_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
+get_group_names(struct xkb_keymap *keymap, struct x11_atom_interner *interner,
xcb_xkb_get_names_reply_t *reply,
xcb_xkb_get_names_value_list_t *list)
{
@@ -968,9 +963,7 @@ get_group_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
keymap->num_group_names = msb_pos(reply->groupNames);
ALLOC_OR_FAIL(keymap->group_names, keymap->num_group_names);
- if (!adopt_atoms(keymap->ctx, conn,
- iter, keymap->group_names, length))
- goto fail;
+ x11_atom_interner_adopt_atoms(interner, iter, keymap->group_names, length);
return true;
@@ -1051,7 +1044,7 @@ fail:
}
static bool
-get_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
+get_names(struct xkb_keymap *keymap, struct x11_atom_interner *interner,
uint16_t device_id)
{
static const xcb_xkb_name_detail_t wanted =
@@ -1072,6 +1065,7 @@ get_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
XCB_XKB_NAME_DETAIL_KEY_NAMES |
XCB_XKB_NAME_DETAIL_VIRTUAL_MOD_NAMES);
+ xcb_connection_t *conn = interner->conn;
xcb_xkb_get_names_cookie_t cookie =
xcb_xkb_get_names(conn, device_id, wanted);
xcb_xkb_get_names_reply_t *reply =
@@ -1097,10 +1091,10 @@ get_names(struct xkb_keymap *keymap, xcb_connection_t *conn,
!get_atom_name(conn, list.symbolsName, &keymap->symbols_section_name) ||
!get_atom_name(conn, list.typesName, &keymap->types_section_name) ||
!get_atom_name(conn, list.compatName, &keymap->compat_section_name) ||
- !get_type_names(keymap, conn, reply, &list) ||
- !get_indicator_names(keymap, conn, reply, &list) ||
- !get_vmod_names(keymap, conn, reply, &list) ||
- !get_group_names(keymap, conn, reply, &list) ||
+ !get_type_names(keymap, interner, reply, &list) ||
+ !get_indicator_names(keymap, interner, reply, &list) ||
+ !get_vmod_names(keymap, interner, reply, &list) ||
+ !get_group_names(keymap, interner, reply, &list) ||
!get_key_names(keymap, conn, reply, &list) ||
!get_aliases(keymap, conn, reply, &list))
goto fail;
@@ -1169,14 +1163,23 @@ xkb_x11_keymap_new_from_device(struct xkb_context *ctx,
if (!keymap)
return NULL;
+ struct x11_atom_interner interner;
+ x11_atom_interner_init(&interner, ctx, conn);
+
if (!get_map(keymap, conn, device_id) ||
!get_indicator_map(keymap, conn, device_id) ||
!get_compat_map(keymap, conn, device_id) ||
- !get_names(keymap, conn, device_id) ||
+ !get_names(keymap, &interner, device_id) ||
!get_controls(keymap, conn, device_id)) {
xkb_keymap_unref(keymap);
return NULL;
}
+ x11_atom_interner_round_trip(&interner);
+ if (interner.had_error) {
+ xkb_keymap_unref(keymap);
+ return NULL;
+ }
+
return keymap;
}
diff --git a/src/x11/util.c b/src/x11/util.c
index 660d885..766e9a0 100644
--- a/src/x11/util.c
+++ b/src/x11/util.c
@@ -169,14 +169,9 @@ struct x11_atom_cache {
size_t len;
};
-bool
-adopt_atoms(struct xkb_context *ctx, xcb_connection_t *conn,
- const xcb_atom_t *from, xkb_atom_t *to, const size_t count)
+static struct x11_atom_cache *
+get_cache(struct xkb_context *ctx, xcb_connection_t *conn)
{
- enum { SIZE = 128 };
- xcb_get_atom_name_cookie_t cookies[SIZE];
- const size_t num_batches = ROUNDUP(count, SIZE) / SIZE;
-
if (!ctx->x11_atom_cache) {
ctx->x11_atom_cache = calloc(1, sizeof(struct x11_atom_cache));
}
@@ -186,79 +181,112 @@ adopt_atoms(struct xkb_context *ctx, xcb_connection_t *conn,
cache->conn = conn;
cache->len = 0;
}
+ return cache;
+}
- memset(to, 0, count * sizeof(*to));
-
- /* Send and collect the atoms in batches of reasonable SIZE. */
- for (size_t batch = 0; batch < num_batches; batch++) {
- const size_t start = batch * SIZE;
- const size_t stop = MIN((batch + 1) * SIZE, count);
-
- /* Send. */
- for (size_t i = start; i < stop; i++) {
- bool cache_hit = false;
- if (cache) {
- for (size_t c = 0; c < cache->len; c++) {
- if (cache->cache[c].from == from[i]) {
- to[i] = cache->cache[c].to;
- cache_hit = true;
- break;
- }
- }
+void
+x11_atom_interner_init(struct x11_atom_interner *interner,
+ struct xkb_context *ctx, xcb_connection_t *conn)
+{
+ interner->had_error = false;
+ interner->ctx = ctx;
+ interner->conn = conn;
+ interner->num_pending = 0;
+ interner->num_copies = 0;
+}
+
+void
+x11_atom_interner_adopt_atom(struct x11_atom_interner *interner,
+ const xcb_atom_t atom, xkb_atom_t *out)
+{
+ *out = 0;
+
+ /* Can be NULL in case the malloc failed. */
+ struct x11_atom_cache *cache = get_cache(interner->ctx, interner->conn);
+
+retry:
+
+ /* Already in the cache? */
+ if (cache) {
+ for (size_t c = 0; c < cache->len; c++) {
+ if (cache->cache[c].from == atom) {
+ *out = cache->cache[c].to;
+ return;
}
- if (!cache_hit && from[i] != XCB_ATOM_NONE)
- cookies[i % SIZE] = xcb_get_atom_name(conn, from[i]);
}
+ }
- /* Collect. */
- for (size_t i = start; i < stop; i++) {
- xcb_get_atom_name_reply_t *reply;
+ /* Already pending? */
+ for (size_t i = 0; i < interner->num_pending; i++) {
+ if (interner->pending[i].from == atom) {
+ if (interner->num_copies == ARRAY_SIZE(interner->copies)) {
+ x11_atom_interner_round_trip(interner);
+ goto retry;
+ }
- if (from[i] == XCB_ATOM_NONE)
- continue;
+ size_t idx = interner->num_copies++;
+ interner->copies[idx].from = atom;
+ interner->copies[idx].out = out;
+ return;
+ }
+ }
- /* Was filled from cache. */
- if (to[i] != 0)
- continue;
+ /* We have to send a GetAtomName request */
+ if (interner->num_pending == ARRAY_SIZE(interner->pending)) {
+ x11_atom_interner_round_trip(interner);
+ assert(interner->num_pending < ARRAY_SIZE(interner->pending));
+ }
+ size_t idx = interner->num_pending++;
+ interner->pending[idx].from = atom;
+ interner->pending[idx].out = out;
+ interner->pending[idx].cookie = xcb_get_atom_name(interner->conn, atom);
+}
- reply = xcb_get_atom_name_reply(conn, cookies[i % SIZE], NULL);
- if (!reply)
- goto err_discard;
+void
+x11_atom_interner_adopt_atoms(struct x11_atom_interner *interner,
+ const xcb_atom_t *from, xkb_atom_t *to,
+ size_t count)
+{
+ for (size_t i = 0; i < count; i++) {
+ x11_atom_interner_adopt_atom(interner, from[i], &to[i]);
+ }
+}
- to[i] = xkb_atom_intern(ctx,
- xcb_get_atom_name_name(reply),
- xcb_get_atom_name_name_length(reply));
- free(reply);
+void x11_atom_interner_round_trip(struct x11_atom_interner *interner) {
+ struct xkb_context *ctx = interner->ctx;
+ xcb_connection_t *conn = interner->conn;
- if (to[i] == XKB_ATOM_NONE)
- goto err_discard;
+ /* Can be NULL in case the malloc failed. */
+ struct x11_atom_cache *cache = get_cache(ctx, conn);
- if (cache && cache->len < ARRAY_SIZE(cache->cache)) {
- size_t idx = cache->len++;
- cache->cache[idx].from = from[i];
- cache->cache[idx].to = to[i];
- }
+ for (size_t i = 0; i < interner->num_pending; i++) {
+ xcb_get_atom_name_reply_t *reply;
+ reply = xcb_get_atom_name_reply(conn, interner->pending[i].cookie, NULL);
+ if (!reply) {
+ interner->had_error = true;
continue;
+ }
+ xcb_atom_t x11_atom = interner->pending[i].from;
+ xkb_atom_t atom = xkb_atom_intern(ctx,
+ xcb_get_atom_name_name(reply),
+ xcb_get_atom_name_name_length(reply));
+ free(reply);
- /*
- * If we don't discard the uncollected replies, they just
- * sit in the XCB queue waiting forever. Sad.
- */
-err_discard:
- for (size_t j = i + 1; j < stop; j++)
- if (from[j] != XCB_ATOM_NONE)
- xcb_discard_reply(conn, cookies[j % SIZE].sequence);
- return false;
+ if (cache && cache->len < ARRAY_SIZE(cache->cache)) {
+ size_t idx = cache->len++;
+ cache->cache[idx].from = x11_atom;
+ cache->cache[idx].to = atom;
}
- }
- return true;
-}
+ *interner->pending[i].out = atom;
-bool
-adopt_atom(struct xkb_context *ctx, xcb_connection_t *conn, xcb_atom_t atom,
- xkb_atom_t *out)
-{
- return adopt_atoms(ctx, conn, &atom, out, 1);
+ for (size_t j = 0; j < interner->num_copies; j++) {
+ if (interner->copies[j].from == x11_atom)
+ *interner->copies[j].out = atom;
+ }
+ }
+
+ interner->num_pending = 0;
+ interner->num_copies = 0;
}
diff --git a/src/x11/x11-priv.h b/src/x11/x11-priv.h
index 3a19e99..5b7f5c2 100644
--- a/src/x11/x11-priv.h
+++ b/src/x11/x11-priv.h
@@ -33,22 +33,44 @@
bool
get_atom_name(xcb_connection_t *conn, xcb_atom_t atom, char **out);
+struct x11_atom_interner {
+ struct xkb_context *ctx;
+ xcb_connection_t *conn;
+ bool had_error;
+ /* Atoms for which we send a GetAtomName request */
+ struct {
+ xcb_atom_t from;
+ xkb_atom_t *out;
+ xcb_get_atom_name_cookie_t cookie;
+ } pending[128];
+ size_t num_pending;
+ /* Atoms which were already pending but queried again */
+ struct {
+ xcb_atom_t from;
+ xkb_atom_t *out;
+ } copies[128];
+ size_t num_copies;
+};
+
+void
+x11_atom_interner_init(struct x11_atom_interner *interner,
+ struct xkb_context *ctx, xcb_connection_t *conn);
+
+void
+x11_atom_interner_round_trip(struct x11_atom_interner *interner);
+
/*
- * Make a xkb_atom_t's from X atoms (prefer to send as many as possible
- * at once, to avoid many roundtrips).
- *
- * TODO: We can make this more flexible, such that @to doesn't have to
- * be sequential. Then we can convert most adopt_atom() calls to
- * adopt_atoms().
- * Atom caching would also likely be useful for avoiding quite a
- * few requests.
+ * Make a xkb_atom_t's from X atoms. The actual write is delayed until the next
+ * call to x11_atom_interner_round_trip() or when too many atoms are pending.
*/
-bool
-adopt_atoms(struct xkb_context *ctx, xcb_connection_t *conn,
- const xcb_atom_t *from, xkb_atom_t *to, size_t count);
+void
+x11_atom_interner_adopt_atom(struct x11_atom_interner *interner,
+ const xcb_atom_t atom, xkb_atom_t *out);
-bool
-adopt_atom(struct xkb_context *ctx, xcb_connection_t *conn, xcb_atom_t atom,
- xkb_atom_t *out);
+
+void
+x11_atom_interner_adopt_atoms(struct x11_atom_interner *interner,
+ const xcb_atom_t *from, xkb_atom_t *to,
+ size_t count);
#endif