Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756893Ab2KHU1m (ORCPT ); Thu, 8 Nov 2012 15:27:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:9406 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756624Ab2KHU1l (ORCPT ); Thu, 8 Nov 2012 15:27:41 -0500 Date: Thu, 8 Nov 2012 14:27:19 -0600 From: Clark Williams To: Peter Zijlstra Cc: LKML , Thomas Gleixner , Ingo Molnar , Steven Rostedt Subject: [PATCH] sched: add a tuning knob to allow changing RR tmeslice Message-ID: <20121108142719.1e0dfc24@redhat.com> Organization: Red Hat, Inc Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/XnCY1vx3b=+WN5sOpPHLxI9"; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4476 Lines: 146 --Sig_/XnCY1vx3b=+WN5sOpPHLxI9 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Subject: [PATCH] sched: add a tuning knob to allow changing RR timeslice User wanted a facility simliar to the ability on Solaris to adjust the SCHED_RR timeslice value. Add a /proc/sys/kernel scheduler knob named sched_rr_timeslice_ms which 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). Patch against tip/master, currently 3.7-rc3. Signed-off-by: Clark Williams --- include/linux/sched.h | 6 +++++- kernel/sched.c | 19 +++++++++++++++++++ kernel/sched_rt.c | 4 ++-- kernel/sysctl.c | 8 ++++++++ 4 files changed, 34 insertions(+), 3 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 12317b6..214bf27 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2097,11 +2097,15 @@ static inline unsigned int get_sysctl_timer_migrati= on(void) #endif extern unsigned int sysctl_sched_rt_period; extern int sysctl_sched_rt_runtime; - int sched_rt_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); =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); + #ifdef CONFIG_SCHED_AUTOGROUP extern unsigned int sysctl_sched_autogroup_enabled; =20 diff --git a/kernel/sched.c b/kernel/sched.c index cdf9484..c63c3a4 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -120,6 +120,7 @@ * Timeslices get refilled after they expire. */ #define DEF_TIMESLICE (100 * HZ / 1000) +int sched_rr_timeslice =3D DEF_TIMESLICE; =20 /* * single value that denotes runtime =3D=3D period, ie unlimited time. @@ -9614,6 +9615,24 @@ 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)=20 + sched_rr_timeslice =3D sched_rr_timeslice <=3D 0 ?=20 + DEF_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 c108b9c..799dd09 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -1791,7 +1791,7 @@ static void task_tick_rt(struct rq *rq, struct task_s= truct *p, int queued) if (--p->rt.time_slice) return; =20 - p->rt.time_slice =3D DEF_TIMESLICE; + p->rt.time_slice =3D sched_rr_timeslice; =20 /* * Requeue to the end of queue if we are not the only element @@ -1819,7 +1819,7 @@ 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 DEF_TIMESLICE; + return sched_rr_timeslice; else return 0; } diff --git a/kernel/sysctl.c b/kernel/sysctl.c index ea7ec7f..10b1129 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -362,6 +362,14 @@ 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_/XnCY1vx3b=+WN5sOpPHLxI9 Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iEYEARECAAYFAlCcFacACgkQHyuj/+TTEp2GyACdGbY/CF9fH69jUzeCgh66KiVr MK0AmgOFPNwTEqbtFcZhKd++Z2tpeMxQ =+Zv5 -----END PGP SIGNATURE----- --Sig_/XnCY1vx3b=+WN5sOpPHLxI9-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/