Module Name: src
Committed By: jruoho
Date: Fri Mar 11 19:50:34 UTC 2011
Modified Files:
src/distrib/sets/lists/comp: mi
src/share/man/man9/man9.x86: Makefile
Added Files:
src/share/man/man9/man9.x86: tsc.9
Log Message:
Add x86/tsc(9).
To generate a diff of this commit:
cvs rdiff -u -r1.1596 -r1.1597 src/distrib/sets/lists/comp/mi
cvs rdiff -u -r1.2 -r1.3 src/share/man/man9/man9.x86/Makefile
cvs rdiff -u -r0 -r1.1 src/share/man/man9/man9.x86/tsc.9
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/distrib/sets/lists/comp/mi
diff -u src/distrib/sets/lists/comp/mi:1.1596 src/distrib/sets/lists/comp/mi:1.1597
--- src/distrib/sets/lists/comp/mi:1.1596 Thu Mar 10 16:50:10 2011
+++ src/distrib/sets/lists/comp/mi Fri Mar 11 19:50:33 2011
@@ -1,4 +1,4 @@
-# $NetBSD: mi,v 1.1596 2011/03/10 16:50:10 njoly Exp $
+# $NetBSD: mi,v 1.1597 2011/03/11 19:50:33 jruoho Exp $
#
# Note: don't delete entries from here - mark them as "obsolete" instead.
#
@@ -10277,6 +10277,11 @@
./usr/share/man/cat9/x86/nmi.0 comp-sys-catman .cat
./usr/share/man/cat9/x86/nmi_disestablish.0 comp-sys-catman .cat
./usr/share/man/cat9/x86/nmi_establish.0 comp-sys-catman .cat
+./usr/share/man/cat9/x86/tsc.0 comp-sys-catman .cat
+./usr/share/man/cat9/x86/tsc_tc_init.0 comp-sys-catman .cat
+./usr/share/man/cat9/x86/tsc_sync_ap.0 comp-sys-catman .cat
+./usr/share/man/cat9/x86/tsc_sync_bp.0 comp-sys-catman .cat
+./usr/share/man/cat9/x86/tsc_sync_drift.0 comp-sys-catman .cat
./usr/share/man/cat9/x86/x86_msr_xcall.0 comp-sys-catman .cat
./usr/share/man/cat9/xc_broadcast.0 comp-sys-catman .cat
./usr/share/man/cat9/xc_unicast.0 comp-sys-catman .cat
@@ -16158,6 +16163,11 @@
./usr/share/man/html9/x86/nmi.html comp-sys-htmlman html
./usr/share/man/html9/x86/nmi_disestablish.html comp-sys-htmlman html
./usr/share/man/html9/x86/nmi_establish.html comp-sys-htmlman html
+./usr/share/man/html9/x86/tsc.html comp-sys-htmlman html
+./usr/share/man/html9/x86/tsc_tc_init.html comp-sys-htmlman html
+./usr/share/man/html9/x86/tsc_sync_ap.html comp-sys-htmlman html
+./usr/share/man/html9/x86/tsc_sync_bp.html comp-sys-htmlman html
+./usr/share/man/html9/x86/tsc_sync_drift.html comp-sys-htmlman html
./usr/share/man/html9/x86/x86_msr_xcall.html comp-sys-htmlman html
./usr/share/man/html9/xc_broadcast.html comp-sys-htmlman html
./usr/share/man/html9/xc_unicast.html comp-sys-htmlman html
@@ -22297,6 +22307,11 @@
./usr/share/man/man9/x86/nmi.9 comp-sys-man .man
./usr/share/man/man9/x86/nmi_disestablish.9 comp-sys-man .man
./usr/share/man/man9/x86/nmi_establish.9 comp-sys-man .man
+./usr/share/man/man9/x86/tsc.9 comp-sys-man .man
+./usr/share/man/man9/x86/tsc_tc_init.9 comp-sys-man .man
+./usr/share/man/man9/x86/tsc_sync_ap.9 comp-sys-man .man
+./usr/share/man/man9/x86/tsc_sync_bp.9 comp-sys-man .man
+./usr/share/man/man9/x86/tsc_sync_drift.9 comp-sys-man .man
./usr/share/man/man9/x86/x86_msr_xcall.9 comp-sys-man .man
./usr/share/man/man9/xc_broadcast.9 comp-sys-man .man
./usr/share/man/man9/xc_unicast.9 comp-sys-man .man
Index: src/share/man/man9/man9.x86/Makefile
diff -u src/share/man/man9/man9.x86/Makefile:1.2 src/share/man/man9/man9.x86/Makefile:1.3
--- src/share/man/man9/man9.x86/Makefile:1.2 Sat Aug 21 10:32:35 2010
+++ src/share/man/man9/man9.x86/Makefile Fri Mar 11 19:50:33 2011
@@ -1,10 +1,15 @@
-# $NetBSD: Makefile,v 1.2 2010/08/21 10:32:35 jruoho Exp $
+# $NetBSD: Makefile,v 1.3 2011/03/11 19:50:33 jruoho Exp $
-MAN= nmi.9 x86_msr_xcall.9
+MAN= nmi.9 tsc.9 x86_msr_xcall.9
MANSUBDIR=/x86
-MLINKS+=nmi.9 nmi_establish.9
-MLINKS+=nmi.9 nmi_disestablish.9
+MLINKS+=nmi.9 nmi_establish.9 \
+ nmi.9 nmi_disestablish.9
+
+MLINKS+=tsc.9 tsc_tc_init.9 \
+ tsc.9 tsc_sync_ap.9 \
+ tsc.9 tsc_sync_bp.9 \
+ tsc.9 tsc_sync_drift.9
.include <bsd.man.mk>
Added files:
Index: src/share/man/man9/man9.x86/tsc.9
diff -u /dev/null src/share/man/man9/man9.x86/tsc.9:1.1
--- /dev/null Fri Mar 11 19:50:35 2011
+++ src/share/man/man9/man9.x86/tsc.9 Fri Mar 11 19:50:33 2011
@@ -0,0 +1,150 @@
+.\" $NetBSD: tsc.9,v 1.1 2011/03/11 19:50:33 jruoho Exp $
+.\"
+.\" Copyright (c) 2011 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Jukka Ruohonen.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd March 5, 2011
+.Dt TSC 9 x86
+.Os
+.Sh NAME
+.Nm tsc
+.Nd Time Stamp Counter
+.Sh SYNOPSIS
+.In x86/x86/tsc.h
+.Ft void
+.Fn tsc_tc_init "void"
+.Ft void
+.Fn tsc_sync_ap "struct cpu_info *ci"
+.Ft void
+.Fn tsc_sync_bp "struct cpu_info *ci"
+.Ft void
+.Fn tsc_sync_drift "int64_t drift"
+.Sh DESCRIPTION
+The time stamp sounter
+.Pq Tn TSC
+is a hardware counter found in all contemporary x86 processors.
+The counter is implemented as a 64-bit model-specific register
+.Pq Tn MSR
+that is incremented at every clock cycle.
+The
+.Tn RDTSC
+.Pq Dq read time stamp counter
+register has been present since the original Pentium.
+.Pp
+Already because of the access method,
+.Tn TSC
+has traditionally provided a low-overhead and high-resolution
+way to obtain
+.Tn CPU
+timing information.
+Recently, however, this reliability has been undermined by
+such factors as system sleep states,
+.Tn CPU
+.Dq hotplugging ,
+.Dq hiberanation ,
+and
+.Tn CPU
+frequency scaling.
+.Pp
+These potential new sources of unreliability are easily understandable
+when one recalls that the counter measures cycles and not
+.Dq time .
+Comparing the cycle counts only makes sense when the clock frequency
+is stable; to convert the cycle counts to time units, a general equation
+would be:
+.Dq seconds = cycles / frequency in Hz .
+The use of
+.Tn TSC
+as a source of high-resolution timing can be thus discouraged.
+But the basic premise is still guaranteed:
+.Tn TSC
+is a monotonically increasing counter.
+.Sh FUNCTIONS
+.Bl -tag -width abcd
+.It Fn tsc_tc_init ""
+The
+.Fn tsc_tc_init
+function initializes the
+.Tn TSC
+as a
+.Xr timecounter 9 .
+The function is called early in the boot process when the processors attach.
+.It Fn tsc_sync_ap "ci"
+The
+.Fn tsc_sync_ap
+function synchronizes the counter for the boot processor
+.Pq Tn BP .
+The supplied
+.Fa ci
+must refer to the
+.Tn BP
+itself.
+The
+.Nm
+interface takes internally care of such issues as out-of-order execution,
+where instructions are not necessarily performed in the order of execution,
+possibly causing a misleading cycle count.
+.It Fn tsc_sync_bp "ci"
+The
+.Fn tsc_sync_bp
+function synchronize the counter for the application processor
+.Fa ci .
+Interrupts must be off at machine-level when the function is called.
+.Pp
+It is necessary to call both
+.Fn tsc_sync_ap
+and
+.Fn tsc_sync_bp
+during the boot, but additional synchronization
+may be required also during runtime.
+As an example, the
+.Tn TSC
+needs to be synchronized for all processors when the system resumes from an
+.Xr acpi 4
+sleep state.
+.It Fn tsc_sync_drift "drift"
+Finally, the
+.Fn tsc_sync_drift
+function records
+.Fa drift ,
+measured in clock cycles.
+This is called when the
+.Tn APs
+attach.
+.El
+.\"
+.\" Some references that are not worth adding to the actual page:
+.\"
+.\" http://lwn.net/Articles/209101/
+.\" http://lwn.net/Articles/388188/
+.\" http://lkml.org/lkml/2005/11/4/173
+.\" http://www.ccsl.carleton.ca/~jamuir/rdtscpm1.pdf
+.\"
+.Sh SEE ALSO
+.Xr gettimeofday 2 ,
+.Xr timeval 3 ,
+.Xr timecounter 9
