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fix(vcores): the core-wait escape at 2 s, not 250 ms (#1929) #2127

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NotRexed merged 2 commits into from
Nov 11, 2026
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fix(vcores): the core-wait escape at 2 s, not 250 ms (#1929) #2127

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fix(vcores): the core-wait escape at 2 s, not 250 ms (#1929)
NotRexed Nov 11, 2026
fccfbed
Merge branch 'main' into fix/vcore-escape-2s
NotRexed Nov 11, 2026
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11 changes: 7 additions & 4 deletions host/hos_thread.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1261,8 +1261,11 @@ void hos_thread_log_handles(void) {
then the one waiting longest). A waiter better than a holder asks it to give the core up (vc_kick), which it does at
its next checkpoint (every nn::os call and SVC: hos_vcore_checkpoint), as Horizon would run the better thread at
once. Guest code with no checkpoint (a spin loop) keeps its core, so a waiter that has waited too long runs anyway
without one (an "escape", logged with the holders): HOS_VCORE_ESCAPE_US for a better waiter (default 1000),
HOS_VCORE_ESCAPE_EQ_US otherwise (20000). Every 5 s the log has a "vcores:" line. GetCurrentCoreNumber answers the
without one (an "escape", logged with the holders): HOS_VCORE_ESCAPE_US for a better waiter, HOS_VCORE_ESCAPE_EQ_US
otherwise (both 2000000: 2 s). An escape runs a thread with no core while the holder still runs on it, so two threads
share per-core state (#1929); it is kept only as a deadlock breaker. 250 ms was the default before: on the 25-minute
route it escaped 6-8 times a run, at waits that ended by themselves within 1.2 s (0 escapes at 2 s, frame times the
same or better). Every 5 s the log has a "vcores:" line. GetCurrentCoreNumber answers the
core a thread holds. */
#if !defined(__EMSCRIPTEN__)
static SRWLOCK vc_lock = SRWLOCK_INIT;
Expand Down Expand Up @@ -1341,8 +1344,8 @@ static int64_t vc_env_ns(const char *name, int64_t us) {
static void vc_acquire(HosThread *t) {
static int64_t esc_better = -1, esc_eq, slice;
if (esc_better < 0) {
esc_eq = vc_env_ns("HOS_VCORE_ESCAPE_EQ_US", 250000);
esc_better = vc_env_ns("HOS_VCORE_ESCAPE_US", 250000);
esc_eq = vc_env_ns("HOS_VCORE_ESCAPE_EQ_US", 2000000);
esc_better = vc_env_ns("HOS_VCORE_ESCAPE_US", 2000000);
slice = vc_env_ns("HOS_VCORE_SLICE_US", 2000);
}
AcquireSRWLockExclusive(&vc_lock);
Expand Down
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