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Distribute closed or blocked stream's weight to its siblings 

This also means that at least one stream whose dpri is
NGHTTP2_STREAM_DPRI_TOP exists, its siblings descendants have no
chance to send streams, even if their parent stream has
NGHTTP2_STREAM_DPRI_NODATA.
This commit is contained in:
Tatsuhiro Tsujikawa 2014-10-07 23:52:36 +09:00
parent a225bb29df
commit 03c4092862
3 changed files with 70 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
lib/nghttp2_stream.c
View File

@ -65,6 +65,7 @@ void nghttp2_stream_init(nghttp2_stream *stream, int32_t stream_id,
stream->effective_weight = stream->weight;
stream->sum_dep_weight = 0;
stream->sum_norest_weight = 0;
stream->sum_top_weight = 0;
stream->roots = roots;
stream->root_prev = NULL;
@ -157,6 +158,20 @@ int32_t nghttp2_stream_dep_distributed_effective_weight
return nghttp2_max(1, weight);
}
static int32_t stream_dep_distributed_top_effective_weight
(nghttp2_stream *stream, int32_t weight)
{
if(stream->sum_top_weight == 0) {
return stream->effective_weight;
}
weight = stream->effective_weight * weight / stream->sum_top_weight;
return nghttp2_max(1, weight);
}
static void stream_update_dep_set_rest(nghttp2_stream *stream);
/* Updates effective_weight of descendant streams in subtree of
|stream|. We assume that stream->effective_weight is already set
right. */
@ -165,9 +180,10 @@ static void stream_update_dep_effective_weight(nghttp2_stream *stream)
nghttp2_stream *si;
DEBUGF(fprintf(stderr, "stream: update_dep_effective_weight "
"stream(%p)=%d, weight=%d, sum_norest_weight=%d\n",
"stream(%p)=%d, weight=%d, sum_norest_weight=%d, "
"sum_top_weight=%d\n",
stream, stream->stream_id, stream->weight,
stream->sum_norest_weight));
stream->sum_norest_weight, stream->sum_top_weight));
/* stream->sum_norest_weight == 0 means there is no
NGHTTP2_STREAM_DPRI_TOP under stream */
@ -176,13 +192,38 @@ static void stream_update_dep_effective_weight(nghttp2_stream *stream)
return;
}
/* If there is no direct descendant whose dpri is
NGHTTP2_STREAM_DPRI_TOP, indirect descendants have the chance to
send data, so recursively set weight for descendants. */
if(stream->sum_top_weight == 0) {
for(si = stream->dep_next; si; si = si->sib_next) {
if(si->dpri != NGHTTP2_STREAM_DPRI_REST) {
si->effective_weight = nghttp2_stream_dep_distributed_effective_weight
(stream, si->weight);
}
stream_update_dep_effective_weight(si);
}
return;
}
/* If there is at least one direct descendant whose dpri is
NGHTTP2_STREAM_DPRI_TOP, we won't give a chance to indirect
descendants, since closed or blocked stream's weight is
distributed among its siblings */
for(si = stream->dep_next; si; si = si->sib_next) {
if(si->dpri != NGHTTP2_STREAM_DPRI_REST) {
si->effective_weight = nghttp2_stream_dep_distributed_effective_weight
if(si->dpri == NGHTTP2_STREAM_DPRI_TOP) {
si->effective_weight = stream_dep_distributed_top_effective_weight
(stream, si->weight);
continue;
}
stream_update_dep_effective_weight(si);
if(si->dpri == NGHTTP2_STREAM_DPRI_NO_DATA) {
/* Since we marked NGHTTP2_STREAM_DPRI_TOP under si, we make
them NGHTTP2_STREAM_DPRI_REST again. */
stream_update_dep_set_rest(si->dep_next);
}
}
}
@ -257,14 +298,18 @@ static int stream_update_dep_set_top(nghttp2_stream *stream, nghttp2_pq *pq,
}
/*
* Updates stream->sum_norest_weight recursively. We have to gather
* effective sum of weight of descendants. If stream->dpri ==
* NGHTTP2_STREAM_DPRI_NO_DATA, we have to go deeper and check that
* any of its descendants has dpri value of NGHTTP2_STREAM_DPRI_TOP.
* If so, we have to add weight of its direct descendants to
* stream->sum_norest_weight. To make this work, this function
* returns 1 if any of its descendants has dpri value of
* NGHTTP2_STREAM_DPRI_TOP, otherwise 0.
* Updates stream->sum_norest_weight and stream->sum_top_weight
* recursively. We have to gather effective sum of weight of
* descendants. If stream->dpri == NGHTTP2_STREAM_DPRI_NO_DATA, we
* have to go deeper and check that any of its descendants has dpri
* value of NGHTTP2_STREAM_DPRI_TOP. If so, we have to add weight of
* its direct descendants to stream->sum_norest_weight. To make this
* work, this function returns 1 if any of its descendants has dpri
* value of NGHTTP2_STREAM_DPRI_TOP, otherwise 0.
*
* Calculating stream->sum_top-weight is very simple compared to
* stream->sum_norest_weight. It just adds up the weight of direct
* descendants whose dpri is NGHTTP2_STREAM_DPRI_TOP.
*/
static int stream_update_dep_sum_norest_weight(nghttp2_stream *stream)
{
@ -272,6 +317,7 @@ static int stream_update_dep_sum_norest_weight(nghttp2_stream *stream)
int rv;
stream->sum_norest_weight = 0;
stream->sum_top_weight = 0;
if(stream->dpri == NGHTTP2_STREAM_DPRI_TOP) {
return 1;
@ -289,6 +335,10 @@ static int stream_update_dep_sum_norest_weight(nghttp2_stream *stream)
rv = 1;
stream->sum_norest_weight += si->weight;
}
if(si->dpri == NGHTTP2_STREAM_DPRI_TOP) {
stream->sum_top_weight += si->weight;
}
}
return rv;

3
lib/nghttp2_stream.h
View File

@ -172,6 +172,9 @@ struct nghttp2_stream {
descendant with dpri == NGHTTP2_STREAM_DPRI_TOP. We use this
value to calculate effective weight. */
int32_t sum_norest_weight;
/* sum of weight of direct descendants whose dpri value is
NGHTTP2_STREAM_DPRI_TOP */
int32_t sum_top_weight;
nghttp2_stream_state state;
/* This is bitwise-OR of 0 or more of nghttp2_stream_flag. */
uint8_t flags;

10
tests/nghttp2_session_test.c
View File

@ -6080,10 +6080,9 @@ void test_nghttp2_session_stream_attach_data(void)
CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == a->dpri);
CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == b->dpri);
CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == c->dpri);
CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == d->dpri);
CU_ASSERT(NGHTTP2_STREAM_DPRI_REST == d->dpri);
CU_ASSERT(16 * 16 / 32 == b->effective_weight);
CU_ASSERT(16 * 16 / 32 == d->effective_weight);
CU_ASSERT(16 * 16 / 16 == b->effective_weight);
CU_ASSERT(1 == dd->queued);
@ -6240,13 +6239,12 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == a->dpri);
CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == b->dpri);
CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == c->dpri);
CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == d->dpri);
CU_ASSERT(NGHTTP2_STREAM_DPRI_REST == d->dpri);
CU_ASSERT(NGHTTP2_STREAM_DPRI_TOP == e->dpri);
CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == f->dpri);
CU_ASSERT(16 == b->effective_weight);
CU_ASSERT(16 * 16 / 32 == e->effective_weight);
CU_ASSERT(16 * 16 / 32 == d->effective_weight);
CU_ASSERT(16 * 16 / 16 == e->effective_weight);
CU_ASSERT(32 == a->sum_norest_weight);
CU_ASSERT(16 == c->sum_norest_weight);