Hi Alex,
On 6/03/2020 4:54 am, Alex Menkov wrote:
Hi David,
Thanks you for the review.
On 03/04/2020 17:50, David Holmes wrote:
Hi Alex,
On 5/03/2020 10:30 am, Alex Menkov wrote:
Hi all,
please review the fix for
https://bugs.openjdk.java.net/browse/JDK-8240340
webrev:
http://cr.openjdk.java.net/~amenkov/jdk15/ThreadMXBean_Locks_test/webrev/
changes:
- assertThreadState method: don't re-read thread state throwing
exception (as we got weird error like "Thread WaitingThread is at
WAITING state but is expected to be in Thread.State = WAITING");
- added proper test shutdown on error (made all threads "daemon",
interrupt waiting thread if CheckerThread throws exception);
- if CheckerThread detects error, propagate the exception to main
thread;
The test changes seem fine.
- fixed LockFreeLogger class - it should work for logging from
several threads, but it doesn't. I prefer to simplify it just to keep
ConcurrentLinkedQueue<String>.
LockFreeLogger is also used by ThreadMXBeanStateTest test, but only
by a single thread.
I don't understand your changes here as you've completely changed the
intended design of the logger. The original accumulates log entries
per-thread and then spits them all out (though I'm not clear on the
exact ordering - I don't how to read that stream stuff). The new code
just creates a single queue of log records interleaving entries from
different threads. The simple logger may be all that is needed but it
seems quite different to the intent of the original.
Testing changes in the test I discovered that there is something wrong
with the logger - it printed only part of the records, so I have to look
at the LockFreeLogger class and I don't understand how it was supposed
to work.
About ordering in cumulative log: each record has Integer which used to
sort log entries from all threads (i.e. records from different threads
are printed at the order which log() was called).
Looking at allRecords/records stuff I don't understand how it should be
used. To get logs from different threads in one logger, we needs one
instance. So we create LockFreeLogger (in main thread) and ctor creates
ThreadLocal record and register it in allRecords. Logging from main
thread works fine, but if any other thread tries to log, 1st log() call
creates its own ThreadLocal records (by records.get()) and log records
from this thread go there. But this ThreadLocal records is not
registered in allRecords, so this logging won't be included in final log.
Looks like we need to change log() to something like
Map<Integer, String> recs = records.get();
if (recs.isEmpty()) {
allRecords.add(recs);
}
recs.put(id, String.format(format, params));
Yep good catch - this logger was completely broken.
But all this stuff do exactly the same as simple ConcurrentLinkedQueue
(i.e. lock free ordered list).
At least I don't see other rationale in the stuff.
I'm not certain of intent with the original but I'd always want to see
log entries in chronological order - which is what we now clearly have.
Thanks,
David
--alex
Thanks,
David
--alex
