7457840230
Booting FreeBSD on an EC2 c5.xlarge instance, the loader "twiddles" 810 times over the course of 510 ms, a rate of 1.59 kHz. Even accepting that many systems are slower than this particular VM and will take longer to boot (especially if using spinning-rust disks), this seems like an unhelpfully large amount of twiddling when compared to the ~60 Hz frame rate of many displays; printing the twiddles also consumes roughly 10% of the boot time on the aforementioned VM. Setting the default globaldiv to 16 dramatically reduces the time spent printing twiddles to the console while still twiddling at roughly 100 Hz; this should be ample even for systems which take longer to boot and consequently twiddle slower. Note that this can adjusted via the twiddle_divisor variable in loader.conf, but that file is not processed until nearly halfway through the loader's runtime. Reviewed by: allanjude, jrtc27, kevans MFC after: 1 week Sponsored by: https://www.patreon.com/cperciva Differential Revision: <https://reviews.freebsd.org/D32163>
77 lines
2.5 KiB
C
77 lines
2.5 KiB
C
/*-
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* Copyright (c) 1986, 1988, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)subr_prf.c 8.3 (Berkeley) 1/21/94
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include "stand.h"
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/* Extra functions from NetBSD standalone printf.c */
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static u_int globaldiv = 16;
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void
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twiddle(u_int callerdiv)
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{
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static u_int callercnt, globalcnt, pos;
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TSENTER();
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callercnt++;
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if (callerdiv > 1 && (callercnt % callerdiv) != 0) {
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TSEXIT();
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return;
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}
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globalcnt++;
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if (globaldiv > 1 && (globalcnt % globaldiv) != 0) {
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TSEXIT();
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return;
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}
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putchar("|/-\\"[pos++ & 3]);
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putchar('\b');
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TSEXIT();
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}
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void
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twiddle_divisor(u_int gdiv)
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{
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globaldiv = gdiv;
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}
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