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Abandon DATA frame priority adjustment (again) 

We tried several times about this subject, but for the current
HTTP/2.0 priority scheme, we think it is best to serve the highest
priroty streams first (interleaving streams if there are several
higest ones). There are an issue when aggregating several frontend
connections to one connection in backend, but it is HTTP/2.0
spec issue, rather than implementation.
This commit is contained in:
Tatsuhiro Tsujikawa 2013-12-14 17:02:59 +09:00
parent 364501a2cd
commit 41104f7b63
3 changed files with 5 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
lib/nghttp2_outbound_item.h
View File

@ -51,8 +51,6 @@ typedef struct {
nghttp2_frame_category frame_cat; nghttp2_frame_category frame_cat;
/* The priority used in priority comparion */ /* The priority used in priority comparion */
int32_t pri; int32_t pri;
/* The initial priority */
int32_t inipri;
} nghttp2_outbound_item; } nghttp2_outbound_item;
/* /*

30
lib/nghttp2_session.c
View File

@ -424,8 +424,7 @@ static int outbound_item_update_pri
return 0; return 0;
} }
} }
/* We only update initial priority */ item->pri = stream->pri;
item->inipri = stream->pri;
return 1; return 1;
} }
@ -448,7 +447,7 @@ void nghttp2_session_reprioritize_stream
nghttp2_pq_update(&session->ob_pq, update_stream_pri, stream); nghttp2_pq_update(&session->ob_pq, update_stream_pri, stream);
nghttp2_pq_update(&session->ob_ss_pq, update_stream_pri, stream); nghttp2_pq_update(&session->ob_ss_pq, update_stream_pri, stream);
if(stream->deferred_data) { if(stream->deferred_data) {
stream->deferred_data->inipri = pri; stream->deferred_data->pri = pri;
} }
if(session->aob.item) { if(session->aob.item) {
outbound_item_update_pri(session->aob.item, stream); outbound_item_update_pri(session->aob.item, stream);
@ -549,7 +548,6 @@ int nghttp2_session_add_frame(nghttp2_session *session,
free(item); free(item);
return r; return r;
} }
item->inipri = item->pri;
return 0; return 0;
} }
@ -1389,29 +1387,6 @@ nghttp2_outbound_item* nghttp2_session_pop_next_ob_item
} }
} }
/*
* Adjust priority of the DATA frame |item|. In order to prevent the
* low priority streams from starving, lower the priority of the
* |item|. If the resulting priority exceeds NGHTTP2_PRI_DEFAULT,
* back to the original priority.
*/
static void adjust_data_pri(nghttp2_outbound_item *item)
{
if(item->pri == NGHTTP2_PRI_LOWEST) {
item->pri = item->inipri;
return;
}
if(item->pri & 0x40000000) {
item->pri = NGHTTP2_PRI_LOWEST;
return;
}
if(item->pri == 0) {
item->pri = 1;
} else {
item->pri <<= 1;
}
}
/* /*
* Called after a frame is sent. * Called after a frame is sent.
* *
@ -1590,7 +1565,6 @@ static int nghttp2_session_after_frame_sent(nghttp2_session *session)
} else { } else {
nghttp2_outbound_item* next_item; nghttp2_outbound_item* next_item;
next_item = nghttp2_session_get_next_ob_item(session); next_item = nghttp2_session_get_next_ob_item(session);
adjust_data_pri(session->aob.item);
/* If priority of this stream is higher or equal to other stream /* If priority of this stream is higher or equal to other stream
waiting at the top of the queue, we continue to send this waiting at the top of the queue, we continue to send this
data. */ data. */

6
tests/nghttp2_session_test.c
View File

@ -1802,13 +1802,13 @@ void test_nghttp2_session_reprioritize_stream(void)
nghttp2_session_reprioritize_stream(session, stream, 120); nghttp2_session_reprioritize_stream(session, stream, 120);
CU_ASSERT(session->aob.item != NULL); CU_ASSERT(session->aob.item != NULL);
CU_ASSERT(120 == session->aob.item->inipri); CU_ASSERT(120 == session->aob.item->pri);
CU_ASSERT(120 == stream->pri); CU_ASSERT(120 == stream->pri);
CU_ASSERT(5000 == nghttp2_session_get_stream(session, 1)->pri); CU_ASSERT(5000 == nghttp2_session_get_stream(session, 1)->pri);
item = nghttp2_session_get_next_ob_item(session); item = nghttp2_session_get_next_ob_item(session);
CU_ASSERT(5000 == item->inipri); CU_ASSERT(120 == item->pri);
CU_ASSERT(NGHTTP2_HEADERS == OB_CTRL_TYPE(item)); CU_ASSERT(NGHTTP2_HEADERS == OB_CTRL_TYPE(item));
CU_ASSERT(1 == OB_CTRL(item)->hd.stream_id); CU_ASSERT(3 == OB_CTRL(item)->hd.stream_id);
nghttp2_session_del(session); nghttp2_session_del(session);