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Re: Causeless CPU load waves in backend, on windows, 9.5.5 (EDB binary).

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02.02.2017 2:14, I wrote:
01.02.2017 1:02, I wrote:
[...]
Could you use process monitor or such to see what the process is doing
while using a lot of CPU?

I'm not sure how to do this, especially considering that the process in
question is running as a service?

Now, some more input:

* 9.5.2 server running on linux x86_64 - unaffected! (What a relief! We
are moving to Centos soon anyway!)

* 9.4.4 server running on win7 32-bit - affected, same thing as on XP.

I've managed to create a "fix" (see diff below).
It looks like the wait logic is somehow broken on windows currently,
though I can not find the problem myself yet.
It would be great if someone more familiar with the (windows-specific)
code came up with ideas.
I have a build environment ready so I could do more tests then.

Some update.

Adding this "Sleep(15)" before "goto retry" into secure_read() has apparently eliminated the effect at our production server too. That is, my load-bug-detector has been quiet for > 24hr or more.

Now by adding more debigging stuff into secure_read() and secure_write() I've found that:

* secure_write() is likely irrelevant, as "goto retry" there was never actually hit yet;

* in secure_read(), during the intervals of excessive cpu load, WaitLatchOrSocket() was never observed to indicate latch event, and was never observed to (erroneously) indicate socket readiness more than once (with socket read attempt in between), which I was suspecting happening, so I can not blame secure_read() itself and this all makes me wonder even more...

Note: I'm testing with SSL off now.

As always, and hints greatly appreciated!


Thank you.
Nikolai


--- be-secure.c.orig 2017-02-01 22:37:37.228032608 +0300
+++ be-secure.c 2017-02-01 22:51:17.655751292 +0300
@@ -159,6 +159,7 @@
* socket to become ready again.
*/
}
+ Sleep(15); /* n.zhubr */
goto retry;
}

@@ -238,6 +239,7 @@
* socket to become ready again.
*/
}
+ Sleep(15); /* n.zhubr */
goto retry;
}


Thank you.

Nikolai



Thank you.

Nikolai


Regards,

Andres










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