From nobody Fri Jan 10 16:37:08 2025 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4YV6kn6k7Kz5kchS for ; Fri, 10 Jan 2025 16:37:21 +0000 (UTC) (envelope-from jrtc27@jrtc27.com) Received: from mail-wr1-f54.google.com (mail-wr1-f54.google.com [209.85.221.54]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "WR4" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4YV6kn4w04z42Ql for ; Fri, 10 Jan 2025 16:37:21 +0000 (UTC) (envelope-from jrtc27@jrtc27.com) Authentication-Results: mx1.freebsd.org; none Received: by mail-wr1-f54.google.com with SMTP id ffacd0b85a97d-38632b8ae71so1582976f8f.0 for ; Fri, 10 Jan 2025 08:37:21 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1736527040; x=1737131840; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=SegSh1p2WklrEWPOaQjOv7J3RTEVNkgy2UuUWwZ0WBM=; b=NbsKHzjUKHUBmcEpz/pFlVjL6aayrPRA6ekeZMnbL9VgB1SmNbG5FxKrIwgDBN8koj K2tFwymn8OKFR5+PTblSxiIkpjyseqN+DatYLycTbLchDBRHW3Vijr6ICcc0yKnh/0W9 vQDdjlhT3/TP0nIO3HRw7RtE/GOzyPPsDPNKn98wOnQp+gfz7jO11qxm6tFTBHKGzwkU kQuDBzUccNV6PfcSQ3wA2LL6h46YzpnLnE2kL8wuuqu0VmrgCUcJdeG5439K1KcKMj1w FRZTcFkL05GgcStUtpTPBX/PJeMAxFYRvGlfhSb3FrMb6EuBeiUHK7/LC+jvIBqQtcCT uu9A== X-Forwarded-Encrypted: i=1; AJvYcCXC/IMmwKJJh5sON3BWiznyCPyrJ5tHL+FNlPuZmKiEuBR3l7y4gETuMeobHNRIWqTloTM0kvVvC/fU/94fA5PxLxvG/Q==@freebsd.org X-Gm-Message-State: AOJu0Yy9Xe4kJMKzhKCaahSR8bBT4jmXvLKzxhTuuBQdFRoYdApeTyXF qzAXDAuJlUigmi3joLw1gwQ2DcfqAutQcrj3C62Pney7ZOJMki2jMgMo3GvuLeM= X-Gm-Gg: ASbGncuw4G3p0X63yftsp2jmAVHt9qkmliKDTwe1nJ0TUW2uIJCkrTPVlo8aPu/G1xZ Vsta6SnKeyO0vbg8/PBR++Hx45Fn5PrqH4kL6Fy/wAVlHGDZkNTlzSrAbfE4TwRXdHrsoLqVpbO GpiY9T+U3DOZVGG1KzVi/Oqaw0BHjTa91nUuqJA62Es24FD5cKcwcQGCglhCBXlYObC2BoKuR0Z lraBGUN3RMPMuTG3/UsyfIhZeuRZL3iXiNiXI0yPNylDMLKMDp8IsN+MuUeRnO+8PdEoW4= X-Google-Smtp-Source: AGHT+IEKuny5FUkU15R4scJSnIV//vX2MYAt3coN+/lVqOM97UvbRWaGSo1k0V9VOLn960+0ilqPEw== X-Received: by 2002:adf:b1db:0:b0:38a:2658:bbc7 with SMTP id ffacd0b85a97d-38a8730cef4mr6930495f8f.29.1736527039362; Fri, 10 Jan 2025 08:37:19 -0800 (PST) Received: from smtpclient.apple ([131.111.5.201]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38a8e384054sm4955279f8f.36.2025.01.10.08.37.18 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 10 Jan 2025 08:37:18 -0800 (PST) Content-Type: text/plain; charset=utf-8 List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@FreeBSD.org Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3826.300.87.4.3\)) Subject: Re: git: 6b82130e6c9a - main - clock: Add a long ticks variable, ticksl From: Jessica Clarke In-Reply-To: <202501101600.50AG0jk6062308@gitrepo.freebsd.org> Date: Fri, 10 Jan 2025 16:37:08 +0000 Cc: "src-committers@freebsd.org" , "dev-commits-src-all@freebsd.org" , "dev-commits-src-main@freebsd.org" Content-Transfer-Encoding: quoted-printable Message-Id: <9B1B709F-5828-489C-81B5-74ED9E4502FC@freebsd.org> References: <202501101600.50AG0jk6062308@gitrepo.freebsd.org> To: Mark Johnston X-Mailer: Apple Mail (2.3826.300.87.4.3) X-Rspamd-Queue-Id: 4YV6kn4w04z42Ql X-Spamd-Bar: ---- X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:15169, ipnet:209.85.128.0/17, country:US] On 10 Jan 2025, at 16:00, Mark Johnston wrote: >=20 > The branch main has been updated by markj: >=20 > URL: = https://cgit.FreeBSD.org/src/commit/?id=3D6b82130e6c9add4a8892ca897df5a0ec= 04663ea2 >=20 > commit 6b82130e6c9add4a8892ca897df5a0ec04663ea2 > Author: Mark Johnston > AuthorDate: 2025-01-10 15:37:07 +0000 > Commit: Mark Johnston > CommitDate: 2025-01-10 15:42:59 +0000 >=20 > clock: Add a long ticks variable, ticksl >=20 > For compatibility with Linux, it's useful to have a tick counter of > width sizeof(long), but our tick counter is an int. Currently the > linuxkpi tries paper over this difference, but this cannot really = be > done reliably, so it's desirable to have a wider tick counter. = This > change introduces ticksl, keeping the existing ticks variable. >=20 > Follow a suggestion from kib to avoid having to maintain two = separate > counters and to avoid converting existing code to use ticksl: = change > hardclock() to update ticksl instead of ticks, and then use = assembler > directives to make ticks and ticksl overlap such that loading ticks > gives the bottom 32 bits. This makes it possible to use ticksl in = the > linuxkpi without having to convert any native code, and without = making > hardclock() more complicated or expensive. Then, the linuxkpi can = be > modified to use ticksl instead of ticks. >=20 > Reviewed by: olce, kib, emaste > MFC after: 1 month > Differential Revision: https://reviews.freebsd.org/D48383 > --- > sys/conf/files | 1 + > sys/kern/kern_clock.c | 26 ++++++++++++++------------ > sys/kern/kern_tc.c | 4 ++-- > sys/kern/subr_param.c | 2 +- > sys/kern/subr_ticks.s | 44 = ++++++++++++++++++++++++++++++++++++++++++++ > sys/sys/kernel.h | 9 +++++++++ > sys/sys/timetc.h | 2 +- > 7 files changed, 72 insertions(+), 16 deletions(-) >=20 > diff --git a/sys/conf/files b/sys/conf/files > index d358737c5613..a630d9dd72bc 100644 > --- a/sys/conf/files > +++ b/sys/conf/files > @@ -3932,6 +3932,7 @@ kern/subr_stack.c optional ddb | stack | ktr > kern/subr_stats.c optional stats > kern/subr_taskqueue.c standard > kern/subr_terminal.c optional vt > +kern/subr_ticks.s standard > kern/subr_trap.c standard > kern/subr_turnstile.c standard > kern/subr_uio.c standard > diff --git a/sys/kern/kern_clock.c b/sys/kern/kern_clock.c > index 6fa2272ed54a..b11c0d235139 100644 > --- a/sys/kern/kern_clock.c > +++ b/sys/kern/kern_clock.c > @@ -323,7 +323,7 @@ read_cpu_time(long *cp_time) >=20 > #include >=20 > -static int watchdog_ticks; > +static long watchdog_ticks; > static int watchdog_enabled; > static void watchdog_fire(void); > static void watchdog_config(void *, u_int, int *); > @@ -369,10 +369,9 @@ watchdog_attach(void) > int stathz; > int profhz; > int profprocs; > -volatile int ticks; > int psratio; >=20 > -DPCPU_DEFINE_STATIC(int, pcputicks); /* Per-CPU version of ticks. */ > +DPCPU_DEFINE_STATIC(long, pcputicks); /* Per-CPU version of ticks. */ > #ifdef DEVICE_POLLING > static int devpoll_run =3D 0; > #endif > @@ -480,14 +479,14 @@ hardclock(int cnt, int usermode) > struct pstats *pstats; > struct thread *td =3D curthread; > struct proc *p =3D td->td_proc; > - int *t =3D DPCPU_PTR(pcputicks); > - int global, i, newticks; > + long global, newticks, *t; >=20 > /* > * Update per-CPU and possibly global ticks values. > */ > + t =3D DPCPU_PTR(pcputicks); > *t +=3D cnt; > - global =3D ticks; > + global =3D atomic_load_long(&ticksl); > do { > newticks =3D *t - global; > if (newticks <=3D 0) { > @@ -496,7 +495,7 @@ hardclock(int cnt, int usermode) > newticks =3D 0; > break; > } > - } while (!atomic_fcmpset_int(&ticks, &global, *t)); > + } while (!atomic_fcmpset_long(&ticksl, &global, *t)); >=20 > /* > * Run current process's virtual and profile time, as needed. > @@ -525,8 +524,10 @@ hardclock(int cnt, int usermode) > } > #endif /* DEVICE_POLLING */ > if (watchdog_enabled > 0) { > - i =3D atomic_fetchadd_int(&watchdog_ticks, -newticks); > - if (i > 0 && i <=3D newticks) > + long left; > + > + left =3D atomic_fetchadd_long(&watchdog_ticks, -newticks); > + if (left > 0 && left <=3D newticks) > watchdog_fire(); > } > intr_event_handle(clk_intr_event, NULL); > @@ -540,11 +541,12 @@ hardclock(int cnt, int usermode) > void > hardclock_sync(int cpu) > { > - int *t; > + long *t; > + > KASSERT(!CPU_ABSENT(cpu), ("Absent CPU %d", cpu)); > - t =3D DPCPU_ID_PTR(cpu, pcputicks); >=20 > - *t =3D ticks; > + t =3D DPCPU_ID_PTR(cpu, pcputicks); > + *t =3D ticksl; > } >=20 > /* > diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c > index 26f09cb60260..a797a101bf6f 100644 > --- a/sys/kern/kern_tc.c > +++ b/sys/kern/kern_tc.c > @@ -1916,9 +1916,9 @@ SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, = CTLFLAG_RD, &tc_tick, 0, > "Approximate number of hardclock ticks in a millisecond"); >=20 > void > -tc_ticktock(int cnt) > +tc_ticktock(long cnt) > { > - static int count; > + static long count; >=20 > if (mtx_trylock_spin(&tc_setclock_mtx)) { > count +=3D cnt; > diff --git a/sys/kern/subr_param.c b/sys/kern/subr_param.c > index 19169ba63061..f4359efec466 100644 > --- a/sys/kern/subr_param.c > +++ b/sys/kern/subr_param.c > @@ -197,7 +197,7 @@ init_param1(void) > * Arrange for ticks to wrap 10 minutes after boot to help catch > * sign problems sooner. > */ > - ticks =3D INT_MAX - (hz * 10 * 60); > + ticksl =3D INT_MAX - (hz * 10 * 60); >=20 > vn_lock_pair_pause_max =3D hz / 100; > if (vn_lock_pair_pause_max =3D=3D 0) > diff --git a/sys/kern/subr_ticks.s b/sys/kern/subr_ticks.s > new file mode 100644 > index 000000000000..6565ba424137 > --- /dev/null > +++ b/sys/kern/subr_ticks.s > @@ -0,0 +1,44 @@ > +/*- > + * SPDX-License-Identifier: BSD-2-Clause > + * > + * Copyright (c) 2025 Mark Johnston > + */ > + > +/* > + * Define the "ticks" and "ticksl" variables. The former is overlaid = onto the > + * low bits of the latter. > + */ > + > +#if defined(__aarch64__) > +#include > +#include > + > = +GNU_PROPERTY_AARCH64_FEATURE_1_NOTE(GNU_PROPERTY_AARCH64_FEATURE_1_VAL) > +#endif > + > +#ifdef _ILP32 > +#define SIZEOF_TICKSL 4 > +#define TICKSL_INIT .long 0 > +#else > +#define SIZEOF_TICKSL 8 > +#define TICKSL_INIT .quad 0 > +#endif > + > +#if defined(_ILP32) || __BYTE_ORDER__ =3D=3D __ORDER_LITTLE_ENDIAN__ > +#define TICKS_OFFSET 0 > +#else > +#define TICKS_OFFSET 4 > +#endif > + > + .data > + > + .global ticksl > + .type ticksl, %object > + .align SIZEOF_TICKSL > +ticksl: TICKSL_INIT > + .size ticksl, SIZEOF_TICKSL > + > + .global ticks > + .type ticks, %object > +ticks =3Dticksl + TICKS_OFFSET > + .size ticks, 4 This can be simplified to: #if __BYTE_ORDER__ =3D=3D __ORDER_LITTLE_ENDIAN__ #define TICKS_OFFSET 0 #else #define TICKS_OFFSET (__SIZEOF_LONG__ - __SIZEOF_INT__) #endif .data .global ticksl .type ticksl, %object .align __SIZEOF_LONG__ ticksl: .zero __SIZEOF_LONG__ .size ticksl, __SIZEOF_LONG__ .global ticks .type ticks, %object ticks =3Dticksl + TICKS_OFFSET .size ticks, __SIZEOF_INT__ (excuse my mail client stripping the tabs...) No need to check the ABI beyond endianness. Also, shouldn=E2=80=99t these both be in .bss? Jess