141 lines
4.6 KiB
Groff
141 lines
4.6 KiB
Groff
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.\" $NetBSD: i386_pmc_info.2,v 1.1 2001/11/10 06:40:59 gmcgarry Exp $
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.\"
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.\" Copyright (c) 2001 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Gregory McGarry.
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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. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd November 10, 2001
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.Dt i386_PMC_INFO 3 i386
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.Os
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.Sh NAME
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.Nm i386_pmc_info ,
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.Nm i386_pmc_startstop ,
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.Nm i386_pmc_read ,
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.Nd interface to CPU performance counters
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.Sh LIBRARY
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.Lb libi386
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.Sh SYNOPSIS
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.Fd #include <sys/types.h>
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.Fd #include <machine/sysarch.h>
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.Fd #include <machine/specialreg.h>
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.Ft int
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.Fn i386_pmc_info "struct i386_pmc_info_args *ia"
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.Ft int
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.Fn i386_pmc_startstop "struct i386_pmc_startstop_args *ssa"
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.Ft int
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.Fn i386_pmc_read "struct i386_pmc_read_args *ra"
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.Sh DESCRIPTION
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These functions provide an interface to the CPU performance counters
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on the 586-class and 686-class processors.
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.Pp
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.Fn i386_pmc_info
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will return information about the available CPU counters. The
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information is returned in
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.Fa ia
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having the following structure:
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.Bd -literal
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struct i386_pmc_info_args {
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int type;
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int flags;
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};
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.Ed
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.Pp
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The
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.Em type
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member describes the class of performance counters available. Valid
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values are PMC_TYPE_NONE, PMC_TYPE_I586, and PMC_TYPE_I686. The
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.Em flags
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member describes additional capabilities of the processor. Valid
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values are PMC_INFO_HASTSC.
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.Pp
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.Fn i386_pmc_startstop
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is used to start and stop the measurement of the CPU performance
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counters. The argument
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.Fa ssa
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has the following structure:
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.Bd -literal
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struct i386_pmc_startstop_args {
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int counter;
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u_int64_t val;
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u_int8_t event;
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u_int8_t unit;
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u_int8_t compare;
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u_int8_t flags;
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};
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.Ed
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.Pp
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The counter specified by the member
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.Em counter
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is started if the member
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.Em flags
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has PMC_SETUP_KERNEL or PMC_SETUP_USER set, otherwise the counter is
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stopped. The initial value of the counter is set to
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.Em val .
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Additional values for the
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.Em flags
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member are PMC_SETUP_EDGE and PMC_SETUP_INV. The
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.Em event
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member specifies some event written to the control register. The
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.Em unit
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member specifies the measurement units. The
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.Em compare
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member is a mask for the counter.
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.Pp
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.Fn i386_pmc_read
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will return information about a specific CPU counter measured during
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the last measurement period determined by the calling of
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.Fn i386_pmc_startstop .
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The information is returned in
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.Fa ra
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having the following structure:
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.Bd -literal
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struct i386_pmc_read_args {
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int counter;
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u_int64_t val;
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u_int64_t time;
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};
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.Ed
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.Pp
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The counter to read should be specified by the
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.Em counter
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member. Counters are numbered from 0 to PMC_NCOUNTERS. The value of
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the counter is returned in the
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.Em val
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member. The time since epoch, measured in CPU clock cycles, is
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returned in the
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.Em time
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member.
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.Sh RETURN VALUES
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Upon successful completion zero is returned, otherwise -1 is returned
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on failure.
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