VirtualBox

source: vbox/trunk/src/VBox/Runtime/common/time/timesup.cpp@ 54202

Last change on this file since 54202 was 54202, checked in by vboxsync, 10 years ago

IPRT,TM: Implemented GIP TSC delta processing in the RTTimeNanoTS code.

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1/* $Id: timesup.cpp 54202 2015-02-13 17:13:44Z vboxsync $ */
2/** @file
3 * IPRT - Time using SUPLib.
4 */
5
6/*
7 * Copyright (C) 2006-2015 Oracle Corporation
8 *
9 * This file is part of VirtualBox Open Source Edition (OSE), as
10 * available from http://www.virtualbox.org. This file is free software;
11 * you can redistribute it and/or modify it under the terms of the GNU
12 * General Public License (GPL) as published by the Free Software
13 * Foundation, in version 2 as it comes in the "COPYING" file of the
14 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16 *
17 * The contents of this file may alternatively be used under the terms
18 * of the Common Development and Distribution License Version 1.0
19 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20 * VirtualBox OSE distribution, in which case the provisions of the
21 * CDDL are applicable instead of those of the GPL.
22 *
23 * You may elect to license modified versions of this file under the
24 * terms and conditions of either the GPL or the CDDL or both.
25 */
26
27
28/*******************************************************************************
29* Header Files *
30*******************************************************************************/
31#define LOG_GROUP RTLOGGROUP_TIME
32#include <iprt/time.h>
33#include "internal/iprt.h"
34
35#include <iprt/assert.h>
36#include <iprt/err.h>
37#include <iprt/log.h>
38#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
39# include <iprt/asm.h>
40# include <iprt/asm-amd64-x86.h>
41# include <iprt/x86.h>
42# include <VBox/sup.h>
43#endif
44#include "internal/time.h"
45
46
47/*******************************************************************************
48* Internal Functions *
49*******************************************************************************/
50#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
51static DECLCALLBACK(void) rtTimeNanoTSInternalBitch(PRTTIMENANOTSDATA pData, uint64_t u64NanoTS, uint64_t u64DeltaPrev, uint64_t u64PrevNanoTS);
52static DECLCALLBACK(uint64_t) rtTimeNanoTSInternalFallback(PRTTIMENANOTSDATA pData);
53static DECLCALLBACK(uint64_t) rtTimeNanoTSInternalRediscover(PRTTIMENANOTSDATA pData);
54#endif
55
56
57/*******************************************************************************
58* Global Variables *
59*******************************************************************************/
60#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
61/** The previous timestamp value returned by RTTimeNanoTS. */
62static uint64_t g_TimeNanoTSPrev = 0;
63
64/** The RTTimeNanoTS data structure that's passed down to the worker functions. */
65static RTTIMENANOTSDATA g_TimeNanoTSData =
66{
67 /* .pu64Prev = */ &g_TimeNanoTSPrev,
68 /* .pfnBad = */ rtTimeNanoTSInternalBitch,
69 /* .pfnRediscover = */ rtTimeNanoTSInternalRediscover,
70 /* .pvDummy = */ NULL,
71 /* .c1nsSteps = */ 0,
72 /* .cExpired = */ 0,
73 /* .cBadPrev = */ 0,
74 /* .cUpdateRaces = */ 0
75};
76
77/** The index into g_apfnWorkers for the function to use.
78 * This cannot be a pointer because that'll break down in GC due to code relocation. */
79static uint32_t g_iWorker = 0;
80/** Array of rtTimeNanoTSInternal worker functions.
81 * This array is indexed by g_iWorker. */
82static const PFNTIMENANOTSINTERNAL g_apfnWorkers[] =
83{
84# define RTTIMENANO_WORKER_DETECT 0
85 rtTimeNanoTSInternalRediscover,
86
87# define RTTIMENANO_WORKER_LEGACY_SYNC_NO_DELTA 1
88 RTTimeNanoTSLegacySyncNoDelta,
89# define RTTIMENANO_WORKER_LEGACY_SYNC_WITH_DELTA 2
90 RTTimeNanoTSLegacySyncWithDelta,
91# define RTTIMENANO_WORKER_LEGACY_ASYNC 3
92 RTTimeNanoTSLegacyAsync,
93# define RTTIMENANO_WORKER_LEGACY_INVAR_NO_DELTA 4
94 RTTimeNanoTSLFenceInvariantNoDelta,
95# define RTTIMENANO_WORKER_LEGACY_INVAR_WITH_DELTA 5
96 RTTimeNanoTSLFenceInvariantWithDelta,
97
98# define RTTIMENANO_WORKER_LFENCE_SYNC_NO_DELTA 6
99 RTTimeNanoTSLFenceSyncNoDelta,
100# define RTTIMENANO_WORKER_LFENCE_SYNC_WITH_DELTA 7
101 RTTimeNanoTSLFenceSyncWithDelta,
102# define RTTIMENANO_WORKER_LFENCE_ASYNC 8
103 RTTimeNanoTSLFenceAsync,
104# define RTTIMENANO_WORKER_LFENCE_INVAR_NO_DELTA 9
105 RTTimeNanoTSLFenceInvariantNoDelta,
106# define RTTIMENANO_WORKER_LFENCE_INVAR_WITH_DELTA 10
107 RTTimeNanoTSLFenceInvariantWithDelta,
108
109# define RTTIMENANO_WORKER_FALLBACK 11
110 rtTimeNanoTSInternalFallback,
111};
112
113
114/**
115 * Helper function that's used by the assembly routines when something goes bust.
116 *
117 * @param pData Pointer to the data structure.
118 * @param u64NanoTS The calculated nano ts.
119 * @param u64DeltaPrev The delta relative to the previously returned timestamp.
120 * @param u64PrevNanoTS The previously returned timestamp (as it was read it).
121 */
122static DECLCALLBACK(void) rtTimeNanoTSInternalBitch(PRTTIMENANOTSDATA pData, uint64_t u64NanoTS, uint64_t u64DeltaPrev, uint64_t u64PrevNanoTS)
123{
124 pData->cBadPrev++;
125 if ((int64_t)u64DeltaPrev < 0)
126 LogRel(("TM: u64DeltaPrev=%RI64 u64PrevNanoTS=0x%016RX64 u64NanoTS=0x%016RX64\n",
127 u64DeltaPrev, u64PrevNanoTS, u64NanoTS));
128 else
129 Log(("TM: u64DeltaPrev=%RI64 u64PrevNanoTS=0x%016RX64 u64NanoTS=0x%016RX64 (debugging?)\n",
130 u64DeltaPrev, u64PrevNanoTS, u64NanoTS));
131}
132
133/**
134 * Fallback function.
135 */
136static DECLCALLBACK(uint64_t) rtTimeNanoTSInternalFallback(PRTTIMENANOTSDATA pData)
137{
138 PSUPGLOBALINFOPAGE pGip = g_pSUPGlobalInfoPage;
139 if ( pGip
140 && pGip->u32Magic == SUPGLOBALINFOPAGE_MAGIC
141 && ( pGip->u32Mode == SUPGIPMODE_INVARIANT_TSC
142 || pGip->u32Mode == SUPGIPMODE_SYNC_TSC
143 || pGip->u32Mode == SUPGIPMODE_ASYNC_TSC))
144 return rtTimeNanoTSInternalRediscover(pData);
145 NOREF(pData);
146# ifndef IN_RC
147 return RTTimeSystemNanoTS();
148# else
149 return 0;
150# endif
151}
152
153
154/**
155 * Checks if we really need to apply the delta values.
156 *
157 * Getting the delta for a CPU is _very_ expensive, it more than doubles the
158 * execution time for RTTimeNanoTS.
159 *
160 * @returns true if deltas needs to be applied, false if not.
161 * @param pGip The GIP.
162 */
163static bool rtTimeNanoTsInternalReallyNeedDeltas(PSUPGLOBALINFOPAGE pGip)
164{
165 if (!pGip->fOsTscDeltasInSync)
166 {
167 uint32_t i = pGip->cCpus;
168 while (i-- > 0)
169 if ( pGip->aCPUs[i].enmState == SUPGIPCPUSTATE_ONLINE
170 && ( pGip->aCPUs[i].i64TSCDelta > 384
171 || pGip->aCPUs[i].i64TSCDelta < -384) )
172 return true;
173 }
174 return false;
175}
176
177
178/**
179 * Called the first time somebody asks for the time or when the GIP
180 * is mapped/unmapped.
181 */
182static DECLCALLBACK(uint64_t) rtTimeNanoTSInternalRediscover(PRTTIMENANOTSDATA pData)
183{
184 uint32_t iWorker;
185 PSUPGLOBALINFOPAGE pGip = g_pSUPGlobalInfoPage;
186 if ( pGip
187 && pGip->u32Magic == SUPGLOBALINFOPAGE_MAGIC
188 && ( pGip->u32Mode == SUPGIPMODE_INVARIANT_TSC
189 || pGip->u32Mode == SUPGIPMODE_SYNC_TSC
190 || pGip->u32Mode == SUPGIPMODE_ASYNC_TSC))
191 {
192 if (ASMCpuId_EDX(1) & X86_CPUID_FEATURE_EDX_SSE2)
193 iWorker = pGip->u32Mode == SUPGIPMODE_INVARIANT_TSC
194 ? rtTimeNanoTsInternalReallyNeedDeltas(pGip)
195 ? RTTIMENANO_WORKER_LFENCE_INVAR_WITH_DELTA : RTTIMENANO_WORKER_LFENCE_INVAR_NO_DELTA
196 : pGip->u32Mode == SUPGIPMODE_SYNC_TSC
197 ? false /** @todo !rtTimeNanoTsInternalReallyNeedDeltas(pGip) */
198 ? RTTIMENANO_WORKER_LFENCE_SYNC_WITH_DELTA : RTTIMENANO_WORKER_LFENCE_SYNC_NO_DELTA
199 : RTTIMENANO_WORKER_LFENCE_ASYNC;
200 else
201 iWorker = pGip->u32Mode == SUPGIPMODE_INVARIANT_TSC
202 ? rtTimeNanoTsInternalReallyNeedDeltas(pGip)
203 ? RTTIMENANO_WORKER_LEGACY_INVAR_WITH_DELTA : RTTIMENANO_WORKER_LEGACY_INVAR_NO_DELTA
204 : pGip->u32Mode == SUPGIPMODE_SYNC_TSC
205 ? false /** @todo rtTimeNanoTsInternalReallyNeedDeltas(pGip) */
206 ? RTTIMENANO_WORKER_LEGACY_SYNC_WITH_DELTA : RTTIMENANO_WORKER_LEGACY_SYNC_NO_DELTA
207 : RTTIMENANO_WORKER_LEGACY_ASYNC;
208 }
209 else
210 iWorker = RTTIMENANO_WORKER_FALLBACK;
211
212 ASMAtomicWriteU32((uint32_t volatile *)&g_iWorker, iWorker);
213 return g_apfnWorkers[iWorker](pData);
214}
215
216#endif /* !IN_GUEST && !RT_NO_GIP */
217
218
219/**
220 * Internal worker for getting the current nanosecond timestamp.
221 */
222DECLINLINE(uint64_t) rtTimeNanoTSInternal(void)
223{
224#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
225 return g_apfnWorkers[g_iWorker](&g_TimeNanoTSData);
226#else
227 return RTTimeSystemNanoTS();
228#endif
229}
230
231
232/**
233 * Gets the current nanosecond timestamp.
234 *
235 * @returns nanosecond timestamp.
236 */
237RTDECL(uint64_t) RTTimeNanoTS(void)
238{
239 return rtTimeNanoTSInternal();
240}
241RT_EXPORT_SYMBOL(RTTimeNanoTS);
242
243
244/**
245 * Gets the current millisecond timestamp.
246 *
247 * @returns millisecond timestamp.
248 */
249RTDECL(uint64_t) RTTimeMilliTS(void)
250{
251 return rtTimeNanoTSInternal() / 1000000;
252}
253RT_EXPORT_SYMBOL(RTTimeMilliTS);
254
255
256#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
257/**
258 * Debugging the time api.
259 *
260 * @returns the number of 1ns steps which has been applied by RTTimeNanoTS().
261 */
262RTDECL(uint32_t) RTTimeDbgSteps(void)
263{
264 return g_TimeNanoTSData.c1nsSteps;
265}
266RT_EXPORT_SYMBOL(RTTimeDbgSteps);
267
268
269/**
270 * Debugging the time api.
271 *
272 * @returns the number of times the TSC interval expired RTTimeNanoTS().
273 */
274RTDECL(uint32_t) RTTimeDbgExpired(void)
275{
276 return g_TimeNanoTSData.cExpired;
277}
278RT_EXPORT_SYMBOL(RTTimeDbgExpired);
279
280
281/**
282 * Debugging the time api.
283 *
284 * @returns the number of bad previous values encountered by RTTimeNanoTS().
285 */
286RTDECL(uint32_t) RTTimeDbgBad(void)
287{
288 return g_TimeNanoTSData.cBadPrev;
289}
290RT_EXPORT_SYMBOL(RTTimeDbgBad);
291
292
293/**
294 * Debugging the time api.
295 *
296 * @returns the number of update races in RTTimeNanoTS().
297 */
298RTDECL(uint32_t) RTTimeDbgRaces(void)
299{
300 return g_TimeNanoTSData.cUpdateRaces;
301}
302RT_EXPORT_SYMBOL(RTTimeDbgRaces);
303#endif /* !IN_GUEST && !RT_NO_GIP */
304
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