From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756959Ab3AaTw6 (ORCPT ); Thu, 31 Jan 2013 14:52:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:1860 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756571Ab3AaTwz (ORCPT ); Thu, 31 Jan 2013 14:52:55 -0500 Date: Thu, 31 Jan 2013 13:52:42 -0600 From: Clark Williams To: Ingo Molnar Cc: Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Steven Rostedt , LKML Subject: [PATCHv2 2/2] sched/rt: add a tuning knob to allow changing SCHED_RR timeslice Message-ID: <20130131135242.1b77b841@redhat.com> Organization: Red Hat, Inc Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/aqHNxecrAC_KANo6Tbgbhii"; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Sig_/aqHNxecrAC_KANo6Tbgbhii Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Add a /proc/sys/kernel scheduler knob named sched_rr_timeslice_ms that allows global changing of the SCHED_RR timeslice value. User visable value is in milliseconds but is stored as jiffies. Setting to 0 (zero) resets to the default (currently 100ms). Signed-off-by: Clark Williams --- include/linux/sched/sysctl.h | 5 +++++ kernel/sched/core.c | 19 +++++++++++++++++++ kernel/sched/rt.c | 6 ++++-- kernel/sysctl.c | 8 ++++++++ 4 files changed, 36 insertions(+), 2 deletions(-) diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index 912adab..fda131f 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -10,6 +10,11 @@ */ #define RR_TIMESLICE (100 * HZ / 1000) =20 +extern int sched_rr_timeslice; +extern int sched_rr_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos); + /* * control realtime throttling: * diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 26058d0..1c39c33 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7508,6 +7508,25 @@ static int sched_rt_global_constraints(void) } #endif /* CONFIG_RT_GROUP_SCHED */ =20 +int sched_rr_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret; + static DEFINE_MUTEX(mutex); + + mutex_lock(&mutex); + ret =3D proc_dointvec(table, write, buffer, lenp, ppos); + /* make sure that internally we keep jiffies */ + /* also, writing zero resets timeslice to default */ + if (!ret && write) { + sched_rr_timeslice =3D sched_rr_timeslice <=3D 0 ? + RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); + } + mutex_unlock(&mutex); + return ret; +} + int sched_rt_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 7c4a007..0fd9d42 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -7,6 +7,8 @@ =20 #include =20 +int sched_rr_timeslice =3D RR_TIMESLICE; + static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);=20 struct rt_bandwidth def_rt_bandwidth; @@ -2017,7 +2019,7 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) if (--p->rt.time_slice) return; =20 - p->rt.time_slice =3D RR_TIMESLICE; + p->rt.time_slice =3D sched_rr_timeslice; =20 /* * Requeue to the end of queue if we (and all of our ancestors) are the @@ -2048,7 +2050,7 @@ static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task) * Time slice is 0 for SCHED_FIFO tasks */ if (task->policy =3D=3D SCHED_RR) - return RR_TIMESLICE; + return sched_rr_timeslice; else return 0; } diff --git a/kernel/sysctl.c b/kernel/sysctl.c index c88878d..1eabf86 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -403,6 +403,14 @@ static struct ctl_table kern_table[] =3D { .mode =3D 0644, .proc_handler =3D sched_rt_handler, }, + { + .procname =3D "sched_rr_timeslice_ms", + .data =3D &sched_rr_timeslice, + .maxlen =3D sizeof(int), + .mode =3D 0644, + .proc_handler =3D sched_rr_handler, + }, + #ifdef CONFIG_SCHED_AUTOGROUP { .procname =3D "sched_autogroup_enabled", --=20 1.7.11.7 --Sig_/aqHNxecrAC_KANo6Tbgbhii Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iEYEARECAAYFAlEKy4oACgkQHyuj/+TTEp3lAgCfZCbG+gMhds4YnYWnCyWSRrt/ Xr4An39GZNOaBWRA5q/ZW9tvFi3LWQJA =EpUP -----END PGP SIGNATURE----- --Sig_/aqHNxecrAC_KANo6Tbgbhii--