Re: LIO/sec per CPU limit? Is it Hardware or Oracle code?

From: <>
Date: Thu, 10 Aug 2017 08:47:32 +1000
Message-ID: <>

Perhaps a cable connector that has partly come loose? Bad connections can cause slow speeds, internal as well as external.


On 10 August 2017 7:46:04 AM AEST, Henry Poras <> wrote:
>I have two identical servers (or so I am told), but application work
>running 2-3 times slower on one than the other. Using Tanel's snapper,
>see that all active sessions are all on CPU. Viewing top shows me the
>thing, each session pegs a cpu. We also found that it wasn't particular
>that slowed down across severs, but it looked like everything was slow.
>select count(*) from dba_objects showed this behavior as did Jonathan
>Lewis's kill_cpu script. This gave me something to test with. Running a
>10046, I saw the same amount of resource utilization (parse count,
>count, cr count, ...), no contention (wait events), but one server
>2.5 times faster than the other. Looking at session stats through
>I see that the number of session logical reads per sec (~all of which
>consistent reads) is ~ 2.5 times higher on one server than the other.
> explains why it takes one longer to finish.
>So, now what?? Why is one server giving me 350k consistent gets/per
>and the other is ~800k? Is it hardware? /proc/cpuinfo shows the same
>for each box. Is it hidden in the Oracle code path? I realize that not
>LIO are created equal, but how do I check this? I am running on
>Any and all thoughts welcome.

Sent from my Android device with K-9 Mail. Please excuse my brevity.
Received on Thu Aug 10 2017 - 00:47:32 CEST

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