Date: Fri, 14 Jan 2011 12:11:11 -0500 From: John Baldwin <jhb@freebsd.org> To: current@freebsd.org Subject: HEADSUP: Realtime thread scheduling changed Message-ID: <201101141211.11674.jhb@freebsd.org>
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--Boundary-00=_vOIMNWWPyz9Y4cO Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit This is just a heads up that I've committed some changes to how the scheduler handles realtime thread priorities. Please let me know of any issues you encounter with nice, rtprio, or idprio. Note that as a result of these changes, rtprio threads will no longer share priorities with interactive timeshare threads. Instead, rtprio threads are now always more important than non-rt threads. -- John Baldwin --Boundary-00=_vOIMNWWPyz9Y4cO Content-Type: message/rfc822; name="forwarded message" Content-Transfer-Encoding: 7bit Content-Description: John Baldwin <jhb@freebsd.org>: svn commit: r217410 - in head/sys: kern sys Content-Disposition: inline Return-Path: <owner-src-committers@FreeBSD.org> Received: from bigwig.baldwin.cx ([unix socket]) by bigwig.baldwin.cx (Cyrus v2.3.16) with LMTPA; Fri, 14 Jan 2011 12:08:14 -0500 X-Sieve: CMU Sieve 2.3 Received: from bigwig.baldwin.cx (localhost [IPv6:::1]) by bigwig.baldwin.cx (Postfix) with ESMTP id 343138A01D for <john@localhost>; Fri, 14 Jan 2011 12:08:13 -0500 (EST) Received: from cyrus.watson.org [65.122.17.42] by bigwig.baldwin.cx with POP3 (fetchmail-6.3.17) for <john@localhost> (single-drop); Fri, 14 Jan 2011 12:08:13 -0500 (EST) Received: from cyrus.watson.org ([unix socket]) by cyrus.watson.org (Cyrus v2.3.13) with LMTPA; Fri, 14 Jan 2011 12:07:07 -0500 X-Sieve: CMU Sieve 2.3 Received: from mx2.freebsd.org (mx2.freebsd.org [69.147.83.53]) by cyrus.watson.org (Postfix) with ESMTP id 02EFB46B09 for <jhb@cyrus.watson.org>; Fri, 14 Jan 2011 12:07:07 -0500 (EST) Received: from hub.freebsd.org (hub.freebsd.org [IPv6:2001:4f8:fff6::36]) by mx2.freebsd.org (Postfix) with ESMTP id 444C5153A6C for <jhb@cyrus.watson.org>; Fri, 14 Jan 2011 17:06:59 +0000 (UTC) Received: by hub.freebsd.org (Postfix) id BD9B0106566B; Fri, 14 Jan 2011 17:06:56 +0000 (UTC) Delivered-To: jhb@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 538) id 0F20C1065675; Fri, 14 Jan 2011 17:06:56 +0000 (UTC) Delivered-To: src-committers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6999610656A6; Fri, 14 Jan 2011 17:06:54 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 57D1A8FC34; Fri, 14 Jan 2011 17:06:54 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id p0EH6sae094828; Fri, 14 Jan 2011 17:06:54 GMT (envelope-from jhb@svn.freebsd.org) Received: (from jhb@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id p0EH6sXq094823; Fri, 14 Jan 2011 17:06:54 GMT (envelope-from jhb@svn.freebsd.org) Message-Id: <201101141706.p0EH6sXq094823@svn.freebsd.org> From: John Baldwin <jhb@FreeBSD.org> Date: Fri, 14 Jan 2011 17:06:54 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r217410 - in head/sys: kern sys X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: owner-src-committers@FreeBSD.org Precedence: bulk X-Loop: FreeBSD.ORG X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.2.6 (bigwig.baldwin.cx); Fri, 14 Jan 2011 12:08:13 -0500 (EST) X-Virus-Scanned: clamav-milter 0.96.3 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-1.9 required=4.2 tests=BAYES_00, TVD_RCVD_SPACE_BRACKET, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on bigwig.baldwin.cx X-Length: 9004 X-UID: 54245 Author: jhb Date: Fri Jan 14 17:06:54 2011 New Revision: 217410 URL: http://svn.freebsd.org/changeset/base/217410 Log: Rework realtime priority support: - Move the realtime priority range up above kernel sleep priorities and just below interrupt thread priorities. - Contract the interrupt and kernel sleep priority ranges a bit so that the timesharing priority band can be increased. The new timeshare range is now slightly larger than the old realtime + timeshare ranges. - Change the ULE scheduler to no longer use realtime priorities for interactive threads. Instead, the larger timeshare range is now split into separate subranges for interactive and non-interactive ("batch") threads. The end result is that interactive threads and non-interactive threads still use the same priority ranges as before, but realtime threads now have a separate, dedicated priority range. - Do not modify the priority of non-timeshare threads in sched_sleep() or via cv_broadcastpri(). Realtime and idle priority threads will no longer have their priorities affected by sleeping in the kernel. Reviewed by: jeff Modified: head/sys/kern/sched_4bsd.c head/sys/kern/sched_ule.c head/sys/kern/subr_sleepqueue.c head/sys/sys/priority.h Modified: head/sys/kern/sched_4bsd.c ============================================================================== --- head/sys/kern/sched_4bsd.c Fri Jan 14 16:42:13 2011 (r217409) +++ head/sys/kern/sched_4bsd.c Fri Jan 14 17:06:54 2011 (r217410) @@ -908,7 +908,7 @@ sched_sleep(struct thread *td, int pri) THREAD_LOCK_ASSERT(td, MA_OWNED); td->td_slptick = ticks; td->td_sched->ts_slptime = 0; - if (pri) + if (pri != 0 && PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) sched_prio(td, pri); if (TD_IS_SUSPENDED(td) || pri >= PSOCK) td->td_flags |= TDF_CANSWAP; Modified: head/sys/kern/sched_ule.c ============================================================================== --- head/sys/kern/sched_ule.c Fri Jan 14 16:42:13 2011 (r217409) +++ head/sys/kern/sched_ule.c Fri Jan 14 17:06:54 2011 (r217410) @@ -118,11 +118,17 @@ static struct td_sched td_sched0; /* * Priority ranges used for interactive and non-interactive timeshare - * threads. Interactive threads use realtime priorities. - */ -#define PRI_MIN_INTERACT PRI_MIN_REALTIME -#define PRI_MAX_INTERACT PRI_MAX_REALTIME -#define PRI_MIN_BATCH PRI_MIN_TIMESHARE + * threads. The timeshare priorities are split up into four ranges. + * The first range handles interactive threads. The last three ranges + * (NHALF, x, and NHALF) handle non-interactive threads with the outer + * ranges supporting nice values. + */ +#define PRI_TIMESHARE_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1) +#define PRI_INTERACT_RANGE ((PRI_TIMESHARE_RANGE - SCHED_PRI_NRESV) / 2) + +#define PRI_MIN_INTERACT PRI_MIN_TIMESHARE +#define PRI_MAX_INTERACT (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE - 1) +#define PRI_MIN_BATCH (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE) #define PRI_MAX_BATCH PRI_MAX_TIMESHARE /* @@ -1893,6 +1899,8 @@ sched_sleep(struct thread *td, int prio) td->td_slptick = ticks; if (TD_IS_SUSPENDED(td) || prio >= PSOCK) td->td_flags |= TDF_CANSWAP; + if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE) + return; if (static_boost == 1 && prio) sched_prio(td, prio); else if (static_boost && td->td_priority > static_boost) Modified: head/sys/kern/subr_sleepqueue.c ============================================================================== --- head/sys/kern/subr_sleepqueue.c Fri Jan 14 16:42:13 2011 (r217409) +++ head/sys/kern/subr_sleepqueue.c Fri Jan 14 17:06:54 2011 (r217410) @@ -745,7 +745,8 @@ sleepq_resume_thread(struct sleepqueue * /* Adjust priority if requested. */ MPASS(pri == 0 || (pri >= PRI_MIN && pri <= PRI_MAX)); - if (pri != 0 && td->td_priority > pri) + if (pri != 0 && td->td_priority > pri && + PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) sched_prio(td, pri); /* Modified: head/sys/sys/priority.h ============================================================================== --- head/sys/sys/priority.h Fri Jan 14 16:42:13 2011 (r217409) +++ head/sys/sys/priority.h Fri Jan 14 17:06:54 2011 (r217410) @@ -67,10 +67,10 @@ * Priorities range from 0 to 255, but differences of less then 4 (RQ_PPQ) * are insignificant. Ranges are as follows: * - * Interrupt threads: 0 - 63 - * Top half kernel threads: 64 - 127 - * Realtime user threads: 128 - 159 - * Time sharing user threads: 160 - 223 + * Interrupt threads: 0 - 47 + * Realtime user threads: 48 - 79 + * Top half kernel threads: 80 - 119 + * Time sharing user threads: 120 - 223 * Idle user threads: 224 - 255 * * XXX If/When the specific interrupt thread and top half thread ranges @@ -81,7 +81,7 @@ #define PRI_MAX (255) /* Lowest priority. */ #define PRI_MIN_ITHD (PRI_MIN) -#define PRI_MAX_ITHD (PRI_MIN_KERN - 1) +#define PRI_MAX_ITHD (PRI_MIN_REALTIME - 1) #define PI_REALTIME (PRI_MIN_ITHD + 0) #define PI_AV (PRI_MIN_ITHD + 4) @@ -92,8 +92,11 @@ #define PI_SOFT (PRI_MIN_ITHD + 24) #define PI_SWI(x) (PI_SOFT + (x) * RQ_PPQ) -#define PRI_MIN_KERN (64) -#define PRI_MAX_KERN (PRI_MIN_REALTIME - 1) +#define PRI_MIN_REALTIME (48) +#define PRI_MAX_REALTIME (PRI_MIN_KERN - 1) + +#define PRI_MIN_KERN (80) +#define PRI_MAX_KERN (PRI_MIN_TIMESHARE - 1) #define PSWP (PRI_MIN_KERN + 0) #define PVM (PRI_MIN_KERN + 4) @@ -106,10 +109,7 @@ #define PLOCK (PRI_MIN_KERN + 32) #define PPAUSE (PRI_MIN_KERN + 36) -#define PRI_MIN_REALTIME (128) -#define PRI_MAX_REALTIME (PRI_MIN_TIMESHARE - 1) - -#define PRI_MIN_TIMESHARE (160) +#define PRI_MIN_TIMESHARE (120) #define PRI_MAX_TIMESHARE (PRI_MIN_IDLE - 1) #define PUSER (PRI_MIN_TIMESHARE) --Boundary-00=_vOIMNWWPyz9Y4cO--
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