linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: K Prateek Nayak <kprateek.nayak@amd.com>
To: Vincent Guittot <vincent.guittot@linaro.org>,
	mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
	dietmar.eggemann@arm.com, rostedt@goodmis.org,
	bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
	vschneid@redhat.com, linux-kernel@vger.kernel.org,
	parth@linux.ibm.com
Cc: qais.yousef@arm.com, chris.hyser@oracle.com,
	valentin.schneider@arm.com, patrick.bellasi@matbug.net,
	David.Laight@aculab.com, pjt@google.com, pavel@ucw.cz,
	tj@kernel.org, qperret@google.com, tim.c.chen@linux.intel.com,
	joshdon@google.com, timj@gnu.org
Subject: Re: [PATCH v5 3/7] sched: Allow sched_{get,set}attr to change latency_nice of the task
Date: Wed, 12 Oct 2022 20:37:36 +0530	[thread overview]
Message-ID: <4d23ef51-6bb9-0410-77cf-5fe44173eee7@amd.com> (raw)
In-Reply-To: <20220925143908.10846-4-vincent.guittot@linaro.org>

Hello Vincent,

On 9/25/2022 8:09 PM, Vincent Guittot wrote:
> From: Parth Shah <parth@linux.ibm.com>
> 
> Introduce the latency_nice attribute to sched_attr and provide a
> mechanism to change the value with the use of sched_setattr/sched_getattr
> syscall.
> 
> Also add new flag "SCHED_FLAG_LATENCY_NICE" to hint the change in
> latency_nice of the task on every sched_setattr syscall.
> 
> Signed-off-by: Parth Shah <parth@linux.ibm.com>
> [rebase and add a dedicated __setscheduler_latency ]
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
>  include/uapi/linux/sched.h       |  4 +++-
>  include/uapi/linux/sched/types.h | 19 +++++++++++++++++++
>  kernel/sched/core.c              | 24 ++++++++++++++++++++++++
>  tools/include/uapi/linux/sched.h |  4 +++-
>  4 files changed, 49 insertions(+), 2 deletions(-)
> 
> diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h
> index 3bac0a8ceab2..b2e932c25be6 100644
> --- a/include/uapi/linux/sched.h
> +++ b/include/uapi/linux/sched.h
> @@ -132,6 +132,7 @@ struct clone_args {
>  #define SCHED_FLAG_KEEP_PARAMS		0x10
>  #define SCHED_FLAG_UTIL_CLAMP_MIN	0x20
>  #define SCHED_FLAG_UTIL_CLAMP_MAX	0x40
> +#define SCHED_FLAG_LATENCY_NICE		0x80

[1]

>  
>  #define SCHED_FLAG_KEEP_ALL	(SCHED_FLAG_KEEP_POLICY | \
>  				 SCHED_FLAG_KEEP_PARAMS)
> @@ -143,6 +144,7 @@ struct clone_args {
>  			 SCHED_FLAG_RECLAIM		| \
>  			 SCHED_FLAG_DL_OVERRUN		| \
>  			 SCHED_FLAG_KEEP_ALL		| \
> -			 SCHED_FLAG_UTIL_CLAMP)
> +			 SCHED_FLAG_UTIL_CLAMP		| \
> +			 SCHED_FLAG_LATENCY_NICE)
>  
>  #endif /* _UAPI_LINUX_SCHED_H */
> diff --git a/include/uapi/linux/sched/types.h b/include/uapi/linux/sched/types.h
> index f2c4589d4dbf..db1e8199e8c8 100644
> --- a/include/uapi/linux/sched/types.h
> +++ b/include/uapi/linux/sched/types.h
> @@ -10,6 +10,7 @@ struct sched_param {
>  
>  #define SCHED_ATTR_SIZE_VER0	48	/* sizeof first published struct */
>  #define SCHED_ATTR_SIZE_VER1	56	/* add: util_{min,max} */
> +#define SCHED_ATTR_SIZE_VER2	60	/* add: latency_nice */
>  
>  /*
>   * Extended scheduling parameters data structure.
> @@ -98,6 +99,22 @@ struct sched_param {
>   * scheduled on a CPU with no more capacity than the specified value.
>   *
>   * A task utilization boundary can be reset by setting the attribute to -1.
> + *
> + * Latency Tolerance Attributes
> + * ===========================
> + *
> + * A subset of sched_attr attributes allows to specify the relative latency
> + * requirements of a task with respect to the other tasks running/queued in the
> + * system.
> + *
> + * @ sched_latency_nice	task's latency_nice value
> + *
> + * The latency_nice of a task can have any value in a range of
> + * [MIN_LATENCY_NICE..MAX_LATENCY_NICE].
> + *
> + * A task with latency_nice with the value of LATENCY_NICE_MIN can be
> + * taken for a task requiring a lower latency as opposed to the task with
> + * higher latency_nice.
>   */
>  struct sched_attr {
>  	__u32 size;
> @@ -120,6 +137,8 @@ struct sched_attr {
>  	__u32 sched_util_min;
>  	__u32 sched_util_max;
>  
> +	/* latency requirement hints */
> +	__s32 sched_latency_nice;
>  };
>  
>  #endif /* _UAPI_LINUX_SCHED_TYPES_H */
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index ada2d05bd894..6a6116ea4c2c 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -7318,6 +7318,14 @@ static void __setscheduler_params(struct task_struct *p,
>  	p->rt_priority = attr->sched_priority;
>  	p->normal_prio = normal_prio(p);
>  	set_load_weight(p, true);
> +
> +}
> +
> +static void __setscheduler_latency(struct task_struct *p,
> +		const struct sched_attr *attr)
> +{
> +	if (attr->sched_flags & SCHED_FLAG_LATENCY_NICE)
> +		p->latency_nice = attr->sched_latency_nice;
>  }
>  
>  /*
> @@ -7460,6 +7468,13 @@ static int __sched_setscheduler(struct task_struct *p,
>  			return retval;
>  	}
>  
> +	if (attr->sched_flags & SCHED_FLAG_LATENCY_NICE) {
> +		if (attr->sched_latency_nice > MAX_LATENCY_NICE)
> +			return -EINVAL;
> +		if (attr->sched_latency_nice < MIN_LATENCY_NICE)
> +			return -EINVAL;
> +	}
> +
>  	if (pi)
>  		cpuset_read_lock();
>  
> @@ -7494,6 +7509,9 @@ static int __sched_setscheduler(struct task_struct *p,
>  			goto change;
>  		if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)
>  			goto change;
> +		if (attr->sched_flags & SCHED_FLAG_LATENCY_NICE &&
> +		    attr->sched_latency_nice != p->latency_nice)
> +			goto change;
>  
>  		p->sched_reset_on_fork = reset_on_fork;
>  		retval = 0;
> @@ -7582,6 +7600,7 @@ static int __sched_setscheduler(struct task_struct *p,
>  		__setscheduler_params(p, attr);
>  		__setscheduler_prio(p, newprio);
>  	}
> +	__setscheduler_latency(p, attr);
>  	__setscheduler_uclamp(p, attr);
>  
>  	if (queued) {
> @@ -7792,6 +7811,9 @@ static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *a
>  	    size < SCHED_ATTR_SIZE_VER1)
>  		return -EINVAL;
>  
> +	if ((attr->sched_flags & SCHED_FLAG_LATENCY_NICE) &&
> +	    size < SCHED_ATTR_SIZE_VER2)
> +		return -EINVAL;
>  	/*
>  	 * XXX: Do we want to be lenient like existing syscalls; or do we want
>  	 * to be strict and return an error on out-of-bounds values?
> @@ -8029,6 +8051,8 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
>  	get_params(p, &kattr);
>  	kattr.sched_flags &= SCHED_FLAG_ALL;
>  
> +	kattr.sched_latency_nice = p->latency_nice;
> +
>  #ifdef CONFIG_UCLAMP_TASK
>  	/*
>  	 * This could race with another potential updater, but this is fine
> diff --git a/tools/include/uapi/linux/sched.h b/tools/include/uapi/linux/sched.h
> index 3bac0a8ceab2..ecc4884bfe4b 100644
> --- a/tools/include/uapi/linux/sched.h
> +++ b/tools/include/uapi/linux/sched.h
> @@ -132,6 +132,7 @@ struct clone_args {
>  #define SCHED_FLAG_KEEP_PARAMS		0x10
>  #define SCHED_FLAG_UTIL_CLAMP_MIN	0x20
>  #define SCHED_FLAG_UTIL_CLAMP_MAX	0x40
> +#define SCHED_FLAG_LATENCY_NICE		0X80

Small nit.
Can you change the "x" in "0X80" to lower case here to make it
consistent with [1] and other #define in the same file. When building
tools like perf, I see the following warning:

Warning: Kernel ABI header at 'tools/include/uapi/linux/sched.h' differs from latest version at 'include/uapi/linux/sched.h'
diff -u tools/include/uapi/linux/sched.h include/uapi/linux/sched.h

Following is the output of
diff -u tools/include/uapi/linux/sched.h include/uapi/linux/sched.h

--- tools/include/uapi/linux/sched.h    2022-10-12 14:56:00.925360275 +0000
+++ include/uapi/linux/sched.h  2022-10-12 14:56:00.917360219 +0000
@@ -132,7 +132,7 @@
 #define SCHED_FLAG_KEEP_PARAMS         0x10
 #define SCHED_FLAG_UTIL_CLAMP_MIN      0x20
 #define SCHED_FLAG_UTIL_CLAMP_MAX      0x40
-#define SCHED_FLAG_LATENCY_NICE                0X80
+#define SCHED_FLAG_LATENCY_NICE                0x80

 #define SCHED_FLAG_KEEP_ALL    (SCHED_FLAG_KEEP_POLICY | \
                                 SCHED_FLAG_KEEP_PARAMS)
--

>  
>  #define SCHED_FLAG_KEEP_ALL	(SCHED_FLAG_KEEP_POLICY | \
>  				 SCHED_FLAG_KEEP_PARAMS)
> @@ -143,6 +144,7 @@ struct clone_args {
>  			 SCHED_FLAG_RECLAIM		| \
>  			 SCHED_FLAG_DL_OVERRUN		| \
>  			 SCHED_FLAG_KEEP_ALL		| \
> -			 SCHED_FLAG_UTIL_CLAMP)
> +			 SCHED_FLAG_UTIL_CLAMP		| \
> +			 SCHED_FLAG_LATENCY_NICE)
>  
>  #endif /* _UAPI_LINUX_SCHED_H */

--
Thanks and Regards,
Prateek

  reply	other threads:[~2022-10-12 15:08 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-25 14:39 [PATCH v5 0/7] Add latency priority for CFS class Vincent Guittot
2022-09-25 14:39 ` [PATCH v5 1/7] sched: Introduce latency-nice as a per-task attribute Vincent Guittot
2022-09-25 14:39 ` [PATCH v5 2/7] sched/core: Propagate parent task's latency requirements to the child task Vincent Guittot
2022-09-25 14:39 ` [PATCH v5 3/7] sched: Allow sched_{get,set}attr to change latency_nice of the task Vincent Guittot
2022-10-12 15:07   ` K Prateek Nayak [this message]
2022-10-12 15:44     ` Vincent Guittot
2022-09-25 14:39 ` [PATCH v5 4/7] sched/fair: Take into account latency priority at wakeup Vincent Guittot
2022-10-22 15:08   ` Chen Yu
2022-10-24 22:36     ` Vincent Guittot
2022-09-25 14:39 ` [PATCH v5 5/7] sched/fair: Add sched group latency support Vincent Guittot
2022-10-12 14:22   ` Qais Yousef
2022-10-12 15:42     ` Vincent Guittot
2022-10-12 16:07       ` Qais Yousef
2022-09-25 14:39 ` [PATCH v5 6/7] sched/core: Support latency priority with sched core Vincent Guittot
2022-09-25 14:39 ` [PATCH v5 7/7] sched/fair: Add latency list Vincent Guittot
2022-10-08  1:04   ` Youssef Esmat
2022-10-08 21:14     ` David Laight
2022-10-08 21:59       ` Steven Rostedt
2022-10-11 17:10     ` Vincent Guittot
2022-10-11 23:54       ` Youssef Esmat
2022-10-12 15:21         ` Vincent Guittot
2022-10-13 17:19           ` Youssef Esmat
2022-10-14 15:22             ` Vincent Guittot
2022-10-19 16:53               ` Vincent Guittot
2022-10-20 15:20                 ` Vincent Guittot
2022-10-26 10:44           ` Dietmar Eggemann
2022-10-26 13:55             ` Vincent Guittot
2022-10-12 14:53 ` [PATCH v5 0/7] Add latency priority for CFS class K Prateek Nayak
2022-10-13 15:24   ` Vincent Guittot
2022-10-17  6:47     ` K Prateek Nayak
2022-10-25  6:36     ` K Prateek Nayak
2022-10-27 16:34       ` Vincent Guittot

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4d23ef51-6bb9-0410-77cf-5fe44173eee7@amd.com \
    --to=kprateek.nayak@amd.com \
    --cc=David.Laight@aculab.com \
    --cc=bristot@redhat.com \
    --cc=bsegall@google.com \
    --cc=chris.hyser@oracle.com \
    --cc=dietmar.eggemann@arm.com \
    --cc=joshdon@google.com \
    --cc=juri.lelli@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mgorman@suse.de \
    --cc=mingo@redhat.com \
    --cc=parth@linux.ibm.com \
    --cc=patrick.bellasi@matbug.net \
    --cc=pavel@ucw.cz \
    --cc=peterz@infradead.org \
    --cc=pjt@google.com \
    --cc=qais.yousef@arm.com \
    --cc=qperret@google.com \
    --cc=rostedt@goodmis.org \
    --cc=tim.c.chen@linux.intel.com \
    --cc=timj@gnu.org \
    --cc=tj@kernel.org \
    --cc=valentin.schneider@arm.com \
    --cc=vincent.guittot@linaro.org \
    --cc=vschneid@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).