aboutsummaryrefslogtreecommitdiffstats
path: root/arch/i386/kernel/smpboot.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/i386/kernel/smpboot.c')
-rw-r--r--arch/i386/kernel/smpboot.c62
1 files changed, 33 insertions, 29 deletions
diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
index 6f5fea05f1d7..f948419c888a 100644
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -212,14 +212,20 @@ valid_k7:
212 * then we print a warning if not, and always resync. 212 * then we print a warning if not, and always resync.
213 */ 213 */
214 214
215static atomic_t tsc_start_flag = ATOMIC_INIT(0); 215static struct {
216static atomic_t tsc_count_start = ATOMIC_INIT(0); 216 atomic_t start_flag;
217static atomic_t tsc_count_stop = ATOMIC_INIT(0); 217 atomic_t count_start;
218static unsigned long long tsc_values[NR_CPUS]; 218 atomic_t count_stop;
219 unsigned long long values[NR_CPUS];
220} tsc __initdata = {
221 .start_flag = ATOMIC_INIT(0),
222 .count_start = ATOMIC_INIT(0),
223 .count_stop = ATOMIC_INIT(0),
224};
219 225
220#define NR_LOOPS 5 226#define NR_LOOPS 5
221 227
222static void __init synchronize_tsc_bp (void) 228static void __init synchronize_tsc_bp(void)
223{ 229{
224 int i; 230 int i;
225 unsigned long long t0; 231 unsigned long long t0;
@@ -233,7 +239,7 @@ static void __init synchronize_tsc_bp (void)
233 /* convert from kcyc/sec to cyc/usec */ 239 /* convert from kcyc/sec to cyc/usec */
234 one_usec = cpu_khz / 1000; 240 one_usec = cpu_khz / 1000;
235 241
236 atomic_set(&tsc_start_flag, 1); 242 atomic_set(&tsc.start_flag, 1);
237 wmb(); 243 wmb();
238 244
239 /* 245 /*
@@ -250,16 +256,16 @@ static void __init synchronize_tsc_bp (void)
250 /* 256 /*
251 * all APs synchronize but they loop on '== num_cpus' 257 * all APs synchronize but they loop on '== num_cpus'
252 */ 258 */
253 while (atomic_read(&tsc_count_start) != num_booting_cpus()-1) 259 while (atomic_read(&tsc.count_start) != num_booting_cpus()-1)
254 cpu_relax(); 260 cpu_relax();
255 atomic_set(&tsc_count_stop, 0); 261 atomic_set(&tsc.count_stop, 0);
256 wmb(); 262 wmb();
257 /* 263 /*
258 * this lets the APs save their current TSC: 264 * this lets the APs save their current TSC:
259 */ 265 */
260 atomic_inc(&tsc_count_start); 266 atomic_inc(&tsc.count_start);
261 267
262 rdtscll(tsc_values[smp_processor_id()]); 268 rdtscll(tsc.values[smp_processor_id()]);
263 /* 269 /*
264 * We clear the TSC in the last loop: 270 * We clear the TSC in the last loop:
265 */ 271 */
@@ -269,56 +275,54 @@ static void __init synchronize_tsc_bp (void)
269 /* 275 /*
270 * Wait for all APs to leave the synchronization point: 276 * Wait for all APs to leave the synchronization point:
271 */ 277 */
272 while (atomic_read(&tsc_count_stop) != num_booting_cpus()-1) 278 while (atomic_read(&tsc.count_stop) != num_booting_cpus()-1)
273 cpu_relax(); 279 cpu_relax();
274 atomic_set(&tsc_count_start, 0); 280 atomic_set(&tsc.count_start, 0);
275 wmb(); 281 wmb();
276 atomic_inc(&tsc_count_stop); 282 atomic_inc(&tsc.count_stop);
277 } 283 }
278 284
279 sum = 0; 285 sum = 0;
280 for (i = 0; i < NR_CPUS; i++) { 286 for (i = 0; i < NR_CPUS; i++) {
281 if (cpu_isset(i, cpu_callout_map)) { 287 if (cpu_isset(i, cpu_callout_map)) {
282 t0 = tsc_values[i]; 288 t0 = tsc.values[i];
283 sum += t0; 289 sum += t0;
284 } 290 }
285 } 291 }
286 avg = sum; 292 avg = sum;
287 do_div(avg, num_booting_cpus()); 293 do_div(avg, num_booting_cpus());
288 294
289 sum = 0;
290 for (i = 0; i < NR_CPUS; i++) { 295 for (i = 0; i < NR_CPUS; i++) {
291 if (!cpu_isset(i, cpu_callout_map)) 296 if (!cpu_isset(i, cpu_callout_map))
292 continue; 297 continue;
293 delta = tsc_values[i] - avg; 298 delta = tsc.values[i] - avg;
294 if (delta < 0) 299 if (delta < 0)
295 delta = -delta; 300 delta = -delta;
296 /* 301 /*
297 * We report bigger than 2 microseconds clock differences. 302 * We report bigger than 2 microseconds clock differences.
298 */ 303 */
299 if (delta > 2*one_usec) { 304 if (delta > 2*one_usec) {
300 long realdelta; 305 long long realdelta;
306
301 if (!buggy) { 307 if (!buggy) {
302 buggy = 1; 308 buggy = 1;
303 printk("\n"); 309 printk("\n");
304 } 310 }
305 realdelta = delta; 311 realdelta = delta;
306 do_div(realdelta, one_usec); 312 do_div(realdelta, one_usec);
307 if (tsc_values[i] < avg) 313 if (tsc.values[i] < avg)
308 realdelta = -realdelta; 314 realdelta = -realdelta;
309 315
310 if (realdelta > 0) 316 if (realdelta)
311 printk(KERN_INFO "CPU#%d had %ld usecs TSC " 317 printk(KERN_INFO "CPU#%d had %Ld usecs TSC "
312 "skew, fixed it up.\n", i, realdelta); 318 "skew, fixed it up.\n", i, realdelta);
313 } 319 }
314
315 sum += delta;
316 } 320 }
317 if (!buggy) 321 if (!buggy)
318 printk("passed.\n"); 322 printk("passed.\n");
319} 323}
320 324
321static void __init synchronize_tsc_ap (void) 325static void __init synchronize_tsc_ap(void)
322{ 326{
323 int i; 327 int i;
324 328
@@ -327,20 +331,20 @@ static void __init synchronize_tsc_ap (void)
327 * this gets called, so we first wait for the BP to 331 * this gets called, so we first wait for the BP to
328 * finish SMP initialization: 332 * finish SMP initialization:
329 */ 333 */
330 while (!atomic_read(&tsc_start_flag)) 334 while (!atomic_read(&tsc.start_flag))
331 cpu_relax(); 335 cpu_relax();
332 336
333 for (i = 0; i < NR_LOOPS; i++) { 337 for (i = 0; i < NR_LOOPS; i++) {
334 atomic_inc(&tsc_count_start); 338 atomic_inc(&tsc.count_start);
335 while (atomic_read(&tsc_count_start) != num_booting_cpus()) 339 while (atomic_read(&tsc.count_start) != num_booting_cpus())
336 cpu_relax(); 340 cpu_relax();
337 341
338 rdtscll(tsc_values[smp_processor_id()]); 342 rdtscll(tsc.values[smp_processor_id()]);
339 if (i == NR_LOOPS-1) 343 if (i == NR_LOOPS-1)
340 write_tsc(0, 0); 344 write_tsc(0, 0);
341 345
342 atomic_inc(&tsc_count_stop); 346 atomic_inc(&tsc.count_stop);
343 while (atomic_read(&tsc_count_stop) != num_booting_cpus()) 347 while (atomic_read(&tsc.count_stop) != num_booting_cpus())
344 cpu_relax(); 348 cpu_relax();
345 } 349 }
346} 350}