jeka/utun2
1
0 Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Verify queue budget saturation and the BBR fast path contract

Browse Source
This commit is contained in:
evgeny committed 2026-10-23 01:02:15 +02:00
1 parent 599d8ad421
commit 34e3d9bba0
1 file changed
+26
Download Patch File Download Diff File Expand all files Collapse all files
tests/test_etcp_bbr.c
+26
View File
@@ -141,6 +141,7 @@ static int test_cwnd_saturation(void) {
bbr_main(&s, &rs, &cwnd, &pacing, 1400, UINT32_MAX - 500, 0);
DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "BBR saturated window: cwnd=%u expected=%u", cwnd, UINT32_MAX);
if (cwnd != UINT32_MAX) FAIL("BDP plus ACK and cwnd plus ACK must saturate, not wrap");
if (s.queue_cwnd_cap != UINT32_MAX) FAIL("large queue budget cap must saturate, not wrap");
PASS(); return 0;
}
@@ -327,6 +328,30 @@ static int test_queue_budget_floor_and_startup(void) {
PASS(); return 0;
}
static void record_window(void* arg, uint32_t window) { *(uint32_t*)arg = window; }
static int test_queue_budget_fast_path(void) {
MSEG("queue budget also bounds fast path and callback");
struct bbr s = { .now_tb = 10000 }; bbr_init(&s);
s.mode = BBR_PROBE_BW; s.full_bw_reached = 1; s.cycle_idx = BBR_BW_PROBE_CRUISE;
s.try_fast_path = 1; s.min_rtt_us = s.probe_rtt_min_us = 20000; s.has_seen_rtt = 1;
s.cycle_mstamp_tb = s.now_tb; s.probe_wait_us = 2000000; s.bw_hi[0] = BW_UNIT; s.queue_budget_us = 5000;
uint32_t cwnd = 100000, pacing = 990000, observed = 0;
s.on_cwnd_update = record_window; s.cwnd_update_ctx = &observed;
struct bbr_rate_sample rs = { .delivered = 1000, .interval_us = 20000, .rtt_us = 20000,
.acked_sacked = 1000, .is_app_limited = 1, .tx_in_flight = 100000 };
bbr_main(&s, &rs, &cwnd, &pacing, 1400, 10000, 0);
if (cwnd != 25000 || observed != cwnd || s.queue_cwnd_cap != cwnd) FAIL("fast path callback must see the bounded window");
s.queue_budget_us = 0; cwnd = 100000; rs.prior_delivered = s.delivered;
bbr_main(&s, &rs, &cwnd, &pacing, 1400, 10000, 0);
if (cwnd != 100000 || observed != cwnd || s.queue_cwnd_cap) FAIL("disabling budget must clear its active cap");
s.queue_budget_us = 5000; s.min_rtt_us = s.probe_rtt_min_us = UINT32_MAX; rs.rtt_us = 0;
rs.prior_delivered = s.delivered;
bbr_main(&s, &rs, &cwnd, &pacing, 1400, 10000, 0);
if (s.queue_cwnd_cap || cwnd != 100000) FAIL("unknown min RTT must not create a fabricated queue cap");
PASS(); return 0;
}
int main(void)
{
debug_config_init(); debug_set_level(DEBUG_LEVEL_ERROR); debug_set_category_level(DEBUG_CATEGORY_DEBUG, DEBUG_LEVEL_INFO);
@@ -347,6 +372,7 @@ int main(void)
test_probe_rtt_lifecycle();
test_queue_budget();
test_queue_budget_floor_and_startup();
test_queue_budget_fast_path();
printf("\n=== Results: %d/%d passed, %d failed ===\n", test_passed, test_total, test_failed);
return test_failed ? 1 : 0;
}