Mercurial > jdk8-mips64-public > hotspot / file comparison
comparison: src/share/vm/memory/genCollectedHeap.cpp
src/share/vm/memory/genCollectedHeap.cpp
- changeset 3339
- e7dead7e90af
- parent 3335
- 3c648b9ad052
- child 3357
- 441e946dc1af
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| 3338:adedfbbf0360 | 3339:e7dead7e90af |
|---|---|
| 1458 _time = MIN2(_time, gen->time_of_last_gc(_now)); | 1458 _time = MIN2(_time, gen->time_of_last_gc(_now)); |
| 1459 } | 1459 } |
| 1460 }; | 1460 }; |
| 1461 | 1461 |
| 1462 jlong GenCollectedHeap::millis_since_last_gc() { | 1462 jlong GenCollectedHeap::millis_since_last_gc() { |
| 1463 jlong now = os::javaTimeMillis(); | 1463 // We need a monotonically non-deccreasing time in ms but |
| 1464 // os::javaTimeMillis() does not guarantee monotonicity. | |
| 1465 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; | |
| 1464 GenTimeOfLastGCClosure tolgc_cl(now); | 1466 GenTimeOfLastGCClosure tolgc_cl(now); |
| 1465 // iterate over generations getting the oldest | 1467 // iterate over generations getting the oldest |
| 1466 // time that a generation was collected | 1468 // time that a generation was collected |
| 1467 generation_iterate(&tolgc_cl, false); | 1469 generation_iterate(&tolgc_cl, false); |
| 1468 tolgc_cl.do_generation(perm_gen()); | 1470 tolgc_cl.do_generation(perm_gen()); |
| 1469 // XXX Despite the assert above, since javaTimeMillis() | 1471 |
| 1470 // doesnot guarantee monotonically increasing return | 1472 // javaTimeNanos() is guaranteed to be monotonically non-decreasing |
| 1471 // values (note, i didn't say "strictly monotonic"), | 1473 // provided the underlying platform provides such a time source |
| 1472 // we need to guard against getting back a time | 1474 // (and it is bug free). So we still have to guard against getting |
| 1473 // later than now. This should be fixed by basing | 1475 // back a time later than 'now'. |
| 1474 // on someting like gethrtime() which guarantees | |
| 1475 // monotonicity. Note that cond_wait() is susceptible | |
| 1476 // to a similar problem, because its interface is | |
| 1477 // based on absolute time in the form of the | |
| 1478 // system time's notion of UCT. See also 4506635 | |
| 1479 // for yet another problem of similar nature. XXX | |
| 1480 jlong retVal = now - tolgc_cl.time(); | 1476 jlong retVal = now - tolgc_cl.time(); |
| 1481 if (retVal < 0) { | 1477 if (retVal < 0) { |
| 1482 NOT_PRODUCT(warning("time warp: %d", retVal);) | 1478 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, retVal);) |
| 1483 return 0; | 1479 return 0; |
| 1484 } | 1480 } |
| 1485 return retVal; | 1481 return retVal; |
| 1486 } | 1482 } |
