From: Con Kolivas <kernel@kolivas.org>
To: Peter Williams <pwil3058@bigpond.net.au>
Cc: Andrew Morton <akpm@osdl.org>, Linus Torvalds <torvalds@osdl.org>,
Ingo Molnar <mingo@elte.hu>,
npiggin@suse.de, "Siddha, Suresh B" <suresh.b.siddha@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched: Consolidated and improved smpnice patch
Date: Mon, 20 Feb 2006 21:02:11 +1100 [thread overview]
Message-ID: <200602202102.14003.kernel@kolivas.org> (raw)
In-Reply-To: <43F94D71.1040109@bigpond.net.au>
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On Monday 20 February 2006 16:02, Peter Williams wrote:
[snip description]
Hi peter, I've had a good look and have just a couple of comments:
---
#endif
int prio, static_prio;
+#ifdef CONFIG_SMP
+ int load_weight; /* for load balancing purposes */
+#endif
---
Can this be moved up to be part of the other ifdef CONFIG_SMP? Not highly
significant since it's in a .h file but looks a tiny bit nicer.
---
+/*
+ * Priority weight for load balancing ranges from 1/20 (nice==19) to 459/20
(RT
+ * priority of 100).
+ */
+#define NICE_TO_LOAD_PRIO(nice) \
+ ((nice >= 0) ? (20 - (nice)) : (20 + (nice) * (nice)))
+#define LOAD_WEIGHT(lp) \
+ (((lp) * SCHED_LOAD_SCALE) / NICE_TO_LOAD_PRIO(0))
+#define NICE_TO_LOAD_WEIGHT(nice) LOAD_WEIGHT(NICE_TO_LOAD_PRIO(nice))
+#define PRIO_TO_LOAD_WEIGHT(prio)
NICE_TO_LOAD_WEIGHT(PRIO_TO_NICE(prio))
+#define RTPRIO_TO_LOAD_WEIGHT(rp) \
+ LOAD_WEIGHT(NICE_TO_LOAD_PRIO(-20) + (rp))
---
The weighting seems not related to anything in particular apart from saying
that -nice values are more heavily weighted. Since you only do this when
setting the priority of tasks can you link it to the scale of (SCHED_NORMAL)
tasks' timeslice instead even though that will take a fraction more
calculation? RTPRIO_TO_LOAD_WEIGHT is fine since there isn't any obvious cpu
proportion relationship to rt_prio level.
Otherwise, good work, thanks!
> Signed-off-by: Peter Williams <pwil3058@bigpond.com.au>
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Cheers,
Con
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next prev parent reply other threads:[~2006-02-20 10:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-20 5:02 [PATCH] sched: Consolidated and improved smpnice patch Peter Williams
2006-02-20 10:02 ` Con Kolivas [this message]
2006-02-20 22:35 ` Peter Williams
2006-02-20 22:41 ` Con Kolivas
2006-02-21 6:21 ` Peter Williams
2006-02-21 9:09 ` Con Kolivas
2006-02-22 0:30 ` Peter Williams
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