Tasks associated to virtual CPUs, IO Threads and Emulator processes can be created with the SCHED_DEADLINE policy. The policy is described in details here: https://docs.kernel.org/scheduler/sched-deadline.html It requires the following parameters (all in nanoseconds): 1) runtime 2) deadline 3) period It must always holds that: runtime <= deadline <= period. The kernel enforces that the values stay within [1024, 2^63-1]. Note, however, that a smaller range could be set (or be already set by default) via sysctl (see kernel.sched_deadline_period_max_us and kernel.sched_deadline_period_min_us). All the three parameters are mandatory but period can be set to 0, in which case it will set to the same value of deadline. Signed-off-by: Sasha Algisi <sasha.algisi@xxxxxxxxxxxx> Signed-off-by: Dario Faggioli <dfaggioli@xxxxxxxx> --- src/ch/ch_process.c | 3 +- src/conf/domain_conf.h | 3 ++ src/qemu/qemu_process.c | 8 +++- src/util/virprocess.c | 84 +++++++++++++++++++++++++++++++++++++++-- src/util/virprocess.h | 6 ++- 5 files changed, 97 insertions(+), 7 deletions(-) diff --git a/src/ch/ch_process.c b/src/ch/ch_process.c index 77f55e777b..a40d188aac 100644 --- a/src/ch/ch_process.c +++ b/src/ch/ch_process.c @@ -293,7 +293,8 @@ virCHProcessSetupPid(virDomainObj *vm, /* Set scheduler type and priority, but not for the main thread. */ if (sched && nameval != VIR_CGROUP_THREAD_EMULATOR && - virProcessSetScheduler(pid, sched->policy, sched->priority) < 0) + virProcessSetScheduler(pid, sched->policy, sched->priority, + sched->runtime, sched->deadline, sched->period) < 0) goto cleanup; ret = 0; diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 060c395943..c3d1a1b65d 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -2454,6 +2454,9 @@ typedef enum { struct _virDomainThreadSchedParam { virProcessSchedPolicy policy; int priority; + uint64_t runtime; + uint64_t deadline; + uint64_t period; }; struct _virDomainTimerCatchupDef { diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 137dcf5cf4..7586e0538a 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -2728,7 +2728,8 @@ qemuProcessSetupPid(virDomainObj *vm, /* Set scheduler type and priority, but not for the main thread. */ if (sched && nameval != VIR_CGROUP_THREAD_EMULATOR && - virProcessSetScheduler(pid, sched->policy, sched->priority) < 0) + virProcessSetScheduler(pid, sched->policy, sched->priority, + sched->runtime, sched->deadline, sched->period) < 0) goto cleanup; ret = 0; @@ -7813,7 +7814,10 @@ qemuProcessLaunch(virConnectPtr conn, if (vm->def->cputune.emulatorsched && virProcessSetScheduler(vm->pid, vm->def->cputune.emulatorsched->policy, - vm->def->cputune.emulatorsched->priority) < 0) + vm->def->cputune.emulatorsched->priority, + vm->def->cputune.emulatorsched->runtime, + vm->def->cputune.emulatorsched->deadline, + vm->def->cputune.emulatorsched->period) < 0) goto cleanup; VIR_DEBUG("Setting any required VM passwords"); diff --git a/src/util/virprocess.c b/src/util/virprocess.c index a8f86784e1..c96bfc45fd 100644 --- a/src/util/virprocess.c +++ b/src/util/virprocess.c @@ -84,6 +84,7 @@ VIR_ENUM_IMPL(virProcessSchedPolicy, "idle", "fifo", "rr", + "deadline", ); @@ -1610,6 +1611,13 @@ virProcessSchedTranslatePolicy(virProcessSchedPolicy policy) case VIR_PROC_POLICY_RR: return SCHED_RR; + case VIR_PROC_POLICY_DEADLINE: +# ifdef SCHED_DEADLINE + return SCHED_DEADLINE; +# else + return -1; +# endif + case VIR_PROC_POLICY_LAST: /* nada */ break; @@ -1621,13 +1629,20 @@ virProcessSchedTranslatePolicy(virProcessSchedPolicy policy) int virProcessSetScheduler(pid_t pid, virProcessSchedPolicy policy, - int priority) + int priority, + uint64_t runtime G_GNUC_UNUSED, + uint64_t deadline G_GNUC_UNUSED, + uint64_t period G_GNUC_UNUSED) { struct sched_param param = {0}; int pol = virProcessSchedTranslatePolicy(policy); - VIR_DEBUG("pid=%lld, policy=%d, priority=%u", - (long long) pid, policy, priority); + VIR_DEBUG("pid=%lld, policy=%d, priority=%u, " + "runtime=%llu, deadline=%llu, period=%llu", + (long long) pid, policy, priority, + (unsigned long long) runtime, + (unsigned long long) deadline, + (unsigned long long) period); if (!policy) return 0; @@ -1667,6 +1682,69 @@ virProcessSetScheduler(pid_t pid, param.sched_priority = priority; } +# ifdef SCHED_DEADLINE + if (pol == SCHED_DEADLINE) { + struct sched_attr attr = {0}; + /* + * The range is enforced in the kernel. + * See: https://man7.org/linux/man-pages/man7/sched.7.html + */ + uint64_t min_value = 1024; + uint64_t max_value = (1ULL << 63) - 1; + + if (runtime < min_value || runtime > max_value) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("Scheduler runtime %llu out of range " + "[%llu, %llu]"), + (unsigned long long) runtime, + (unsigned long long) min_value, + (unsigned long long) max_value); + return -1; + } + + if (deadline < runtime || deadline > max_value) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("Scheduler deadline %llu out of range " + "[%llu, %llu]"), + (unsigned long long) deadline, + (unsigned long long) runtime, + (unsigned long long) max_value); + return -1; + } + + if ((period < deadline || period > max_value) && period != 0) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("Invalid scheduler period %llu, " + "possible correct values are 0 " + "or [%llu, %llu]"), + (unsigned long long) period, + (unsigned long long) deadline, + (unsigned long long) max_value); + return -1; + } + + attr.size = sizeof(attr); + attr.sched_policy = pol; + /* + * Setting reset-on-fork is necessary as SCHED_DEADLINE + * tasks cannot fork. See: + * https://docs.kernel.org/scheduler/sched-deadline.html#default-behavior + */ + attr.sched_flags = SCHED_FLAG_RESET_ON_FORK; + attr.sched_runtime = runtime; + attr.sched_deadline = deadline; + attr.sched_period = period; + + if (sched_setattr(pid, &attr, 0) == 0) { + return 0; + } else { + virReportSystemError(errno, + _("Cannot set scheduler parameters for pid %lld"), + (long long) pid); + return -1; + } + } +# endif if (sched_setscheduler(pid, pol, ¶m) < 0) { virReportSystemError(errno, _("Cannot set scheduler parameters for pid %lld"), diff --git a/src/util/virprocess.h b/src/util/virprocess.h index 30b6981c73..84fdf00fdf 100644 --- a/src/util/virprocess.h +++ b/src/util/virprocess.h @@ -33,6 +33,7 @@ typedef enum { VIR_PROC_POLICY_IDLE, VIR_PROC_POLICY_FIFO, VIR_PROC_POLICY_RR, + VIR_PROC_POLICY_DEADLINE, VIR_PROC_POLICY_LAST } virProcessSchedPolicy; @@ -116,7 +117,10 @@ int virProcessSetupPrivateMountNS(void); int virProcessSetScheduler(pid_t pid, virProcessSchedPolicy policy, - int priority); + int priority, + uint64_t runtime, + uint64_t deadline, + uint64_t period); GStrv virProcessGetStat(pid_t pid, pid_t tid); -- 2.37.1 -- ------------------------ Indirizzo istituzionale di posta elettronica degli studenti e dei laureati dell'Università di TorinoOfficial University of Turin email address for students and graduates
