From: Keir Fraser <keir@xen.org>
To: George Dunlap <George.Dunlap@eu.citrix.com>,
xen-devel@lists.xensource.com
Cc: Tim Deegan <tim@xen.org>
Subject: Re: [PATCH] xen,credit1: Add variable timeslice
Date: Tue, 13 Sep 2011 10:44:06 +0100 [thread overview]
Message-ID: <CA94E476.31792%keir@xen.org> (raw)
In-Reply-To: <CAFLBxZaKkU4-Ghrp2tLqVhdCnzBo6hb36MKQKseOZFvOEf=Ojw@mail.gmail.com>
On 13/09/2011 10:25, "George Dunlap" <George.Dunlap@eu.citrix.com> wrote:
> Ping?
Now done.
-- Keir
> On Thu, Sep 1, 2011 at 4:30 PM, George Dunlap
> <george.dunlap@eu.citrix.com> wrote:
>> Add a xen command-line parameter, sched_credit_tslice_ms,
>> to set the timeslice of the credit1 scheduler.
>>
>> Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
>>
>> diff -r 4a4882df5649 -r 782284c5b1bc xen/common/sched_credit.c
>> --- a/xen/common/sched_credit.c Wed Aug 31 15:23:49 2011 +0100
>> +++ b/xen/common/sched_credit.c Thu Sep 01 16:29:50 2011 +0100
>> @@ -41,15 +41,9 @@
>> */
>> #define CSCHED_DEFAULT_WEIGHT 256
>> #define CSCHED_TICKS_PER_TSLICE 3
>> -#define CSCHED_TICKS_PER_ACCT 3
>> -#define CSCHED_MSECS_PER_TICK 10
>> -#define CSCHED_MSECS_PER_TSLICE \
>> - (CSCHED_MSECS_PER_TICK * CSCHED_TICKS_PER_TSLICE)
>> +/* Default timeslice: 30ms */
>> +#define CSCHED_DEFAULT_TSLICE_MS 30
>> #define CSCHED_CREDITS_PER_MSEC 10
>> -#define CSCHED_CREDITS_PER_TSLICE \
>> - (CSCHED_CREDITS_PER_MSEC * CSCHED_MSECS_PER_TSLICE)
>> -#define CSCHED_CREDITS_PER_ACCT \
>> - (CSCHED_CREDITS_PER_MSEC * CSCHED_MSECS_PER_TICK *
>> CSCHED_TICKS_PER_ACCT)
>>
>>
>> /*
>> @@ -113,6 +107,8 @@
>> */
>> static bool_t __read_mostly sched_credit_default_yield;
>> boolean_param("sched_credit_default_yield", sched_credit_default_yield);
>> +static int __read_mostly sched_credit_tslice_ms = CSCHED_DEFAULT_TSLICE_MS;
>> +integer_param("sched_credit_tslice_ms", sched_credit_tslice_ms);
>>
>> /*
>> * Physical CPU
>> @@ -176,6 +172,9 @@ struct csched_private {
>> uint32_t credit;
>> int credit_balance;
>> uint32_t runq_sort;
>> + /* Period of master and tick in milliseconds */
>> + unsigned tslice_ms, tick_period_us, ticks_per_tslice;
>> + unsigned credits_per_tslice;
>> };
>>
>> static void csched_tick(void *_cpu);
>> @@ -326,7 +325,7 @@ csched_free_pdata(const struct scheduler
>>
>> spin_lock_irqsave(&prv->lock, flags);
>>
>> - prv->credit -= CSCHED_CREDITS_PER_ACCT;
>> + prv->credit -= prv->credits_per_tslice;
>> prv->ncpus--;
>> cpu_clear(cpu, prv->idlers);
>> cpu_clear(cpu, prv->cpus);
>> @@ -360,19 +359,19 @@ csched_alloc_pdata(const struct schedule
>> spin_lock_irqsave(&prv->lock, flags);
>>
>> /* Initialize/update system-wide config */
>> - prv->credit += CSCHED_CREDITS_PER_ACCT;
>> + prv->credit += prv->credits_per_tslice;
>> prv->ncpus++;
>> cpu_set(cpu, prv->cpus);
>> if ( prv->ncpus == 1 )
>> {
>> prv->master = cpu;
>> init_timer(&prv->master_ticker, csched_acct, prv, cpu);
>> - set_timer(&prv->master_ticker, NOW() +
>> - MILLISECS(CSCHED_MSECS_PER_TICK) * CSCHED_TICKS_PER_ACCT);
>> + set_timer(&prv->master_ticker,
>> + NOW() + MILLISECS(prv->tslice_ms));
>> }
>>
>> init_timer(&spc->ticker, csched_tick, (void *)(unsigned long)cpu, cpu);
>> - set_timer(&spc->ticker, NOW() + MILLISECS(CSCHED_MSECS_PER_TICK));
>> + set_timer(&spc->ticker, NOW() + MICROSECS(prv->tick_period_us) );
>>
>> INIT_LIST_HEAD(&spc->runq);
>> spc->runq_sort_last = prv->runq_sort;
>> @@ -1002,7 +1001,7 @@ csched_acct(void* dummy)
>> * for one full accounting period. We allow a domain to earn more
>> * only when the system-wide credit balance is negative.
>> */
>> - credit_peak = sdom->active_vcpu_count * CSCHED_CREDITS_PER_ACCT;
>> + credit_peak = sdom->active_vcpu_count * prv->credits_per_tslice;
>> if ( prv->credit_balance < 0 )
>> {
>> credit_peak += ( ( -prv->credit_balance
>> @@ -1014,7 +1013,7 @@ csched_acct(void* dummy)
>>
>> if ( sdom->cap != 0U )
>> {
>> - credit_cap = ((sdom->cap * CSCHED_CREDITS_PER_ACCT) + 99) / 100;
>> + credit_cap = ((sdom->cap * prv->credits_per_tslice) + 99) / 100;
>> if ( credit_cap < credit_peak )
>> credit_peak = credit_cap;
>>
>> @@ -1092,10 +1091,10 @@ csched_acct(void* dummy)
>> }
>>
>> /* Lower bound on credits */
>> - if ( credit < -CSCHED_CREDITS_PER_TSLICE )
>> + if ( credit < -prv->credits_per_tslice )
>> {
>> CSCHED_STAT_CRANK(acct_min_credit);
>> - credit = -CSCHED_CREDITS_PER_TSLICE;
>> + credit = -prv->credits_per_tslice;
>> atomic_set(&svc->credit, credit);
>> }
>> }
>> @@ -1117,7 +1116,7 @@ csched_acct(void* dummy)
>> }
>>
>> /* Upper bound on credits means VCPU stops earning */
>> - if ( credit > CSCHED_CREDITS_PER_TSLICE )
>> + if ( credit > prv->credits_per_tslice )
>> {
>> __csched_vcpu_acct_stop_locked(prv, svc);
>> /* Divide credits in half, so that when it starts
>> @@ -1141,8 +1140,8 @@ csched_acct(void* dummy)
>> prv->runq_sort++;
>>
>> out:
>> - set_timer( &prv->master_ticker, NOW() +
>> - MILLISECS(CSCHED_MSECS_PER_TICK) * CSCHED_TICKS_PER_ACCT );
>> + set_timer( &prv->master_ticker,
>> + NOW() + MILLISECS(prv->tslice_ms));
>> }
>>
>> static void
>> @@ -1169,7 +1168,7 @@ csched_tick(void *_cpu)
>> */
>> csched_runq_sort(prv, cpu);
>>
>> - set_timer(&spc->ticker, NOW() + MILLISECS(CSCHED_MSECS_PER_TICK));
>> + set_timer(&spc->ticker, NOW() + MICROSECS(prv->tick_period_us) );
>> }
>>
>> static struct csched_vcpu *
>> @@ -1375,7 +1374,7 @@ csched_schedule(
>> * Return task to run next...
>> */
>> ret.time = (is_idle_vcpu(snext->vcpu) ?
>> - -1 : MILLISECS(CSCHED_MSECS_PER_TSLICE));
>> + -1 : MILLISECS(prv->tslice_ms));
>> ret.task = snext->vcpu;
>>
>> CSCHED_VCPU_CHECK(ret.task);
>> @@ -1469,10 +1468,9 @@ csched_dump(const struct scheduler *ops)
>> "\tweight = %u\n"
>> "\trunq_sort = %u\n"
>> "\tdefault-weight = %d\n"
>> - "\tmsecs per tick = %dms\n"
>> + "\ttslice = %dms\n"
>> "\tcredits per msec = %d\n"
>> "\tticks per tslice = %d\n"
>> - "\tticks per acct = %d\n"
>> "\tmigration delay = %uus\n",
>> prv->ncpus,
>> prv->master,
>> @@ -1481,10 +1479,9 @@ csched_dump(const struct scheduler *ops)
>> prv->weight,
>> prv->runq_sort,
>> CSCHED_DEFAULT_WEIGHT,
>> - CSCHED_MSECS_PER_TICK,
>> + prv->tslice_ms,
>> CSCHED_CREDITS_PER_MSEC,
>> - CSCHED_TICKS_PER_TSLICE,
>> - CSCHED_TICKS_PER_ACCT,
>> + prv->ticks_per_tslice,
>> vcpu_migration_delay);
>>
>> cpumask_scnprintf(idlers_buf, sizeof(idlers_buf), prv->idlers);
>> @@ -1526,6 +1523,13 @@ csched_init(struct scheduler *ops)
>> INIT_LIST_HEAD(&prv->active_sdom);
>> prv->master = UINT_MAX;
>>
>> + prv->tslice_ms = sched_credit_tslice_ms;
>> + prv->ticks_per_tslice = CSCHED_TICKS_PER_TSLICE;
>> + if ( prv->tslice_ms < prv->ticks_per_tslice )
>> + prv->ticks_per_tslice = 1;
>> + prv->tick_period_us = prv->tslice_ms * 1000 / prv->ticks_per_tslice;
>> + prv->credits_per_tslice = CSCHED_CREDITS_PER_MSEC * prv->tslice_ms;
>> +
>> return 0;
>> }
>>
>> @@ -1550,13 +1554,16 @@ static void csched_tick_suspend(const st
>>
>> static void csched_tick_resume(const struct scheduler *ops, unsigned int
>> cpu)
>> {
>> + struct csched_private *prv;
>> struct csched_pcpu *spc;
>> uint64_t now = NOW();
>>
>> spc = CSCHED_PCPU(cpu);
>>
>> - set_timer(&spc->ticker, now + MILLISECS(CSCHED_MSECS_PER_TICK)
>> - - now % MILLISECS(CSCHED_MSECS_PER_TICK) );
>> + prv = CSCHED_PRIV(ops);
>> +
>> + set_timer(&spc->ticker, now + MICROSECS(prv->tick_period_us)
>> + - now % MICROSECS(prv->tick_period_us) );
>> }
>>
>> static struct csched_private _csched_priv;
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xensource.com
>> http://lists.xensource.com/xen-devel
>>
prev parent reply other threads:[~2011-09-13 9:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-01 15:30 [PATCH] xen,credit1: Add variable timeslice George Dunlap
2011-09-01 15:49 ` Tim Deegan
2011-09-01 15:45 ` George Dunlap
2011-09-13 9:25 ` George Dunlap
2011-09-13 9:44 ` Keir Fraser [this message]
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