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Former Member
Jul 01, 2015 at 11:11 AM

sp_sysmon reports high IO in threading mode

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Am looking at sp_sysmon output on an 15.7 SP134 server in thread mode and am seeing very high IO reported even though very little running.

We have 15 threads for default and with just 2 SQL processes running sysmon reports

Engine Utilization (Tick %) User Busy System Busy I/O Busy Idle

------------------------- ------------ ------------ ---------- ----------

ThreadPool : syb_default_pool

Engine 0 1.5 % 0.0 % 96.1 % 2.5 %

Engine 1 3.4 % 0.5 % 93.6 % 2.5 %

Engine 2 4.9 % 0.0 % 92.1 % 3.0 %

Engine 3 7.4 % 0.0 % 90.6 % 2.0 %

Engine 4 5.4 % 0.0 % 92.1 % 2.5 %

Engine 5 1.5 % 0.0 % 96.1 % 2.5 %

Engine 6 7.4 % 0.0 % 90.1 % 2.5 %

Engine 7 4.4 % 0.0 % 92.6 % 3.0 %

Engine 8 9.4 % 0.0 % 88.2 % 2.5 %

Engine 9 13.3 % 1.0 % 83.3 % 2.5 %

Engine 10 11.8 % 0.0 % 85.2 % 3.0 %

Engine 11 6.4 % 0.0 % 91.6 % 2.0 %

Engine 12 12.8 % 0.0 % 85.2 % 2.0 %

Engine 13 11.8 % 0.0 % 86.2 % 2.0 %

Engine 14 3.9 % 0.0 % 93.6 % 2.5 %

It seems all the engines are I/O busy- but none of the SQL is doing much SAN or network IO.

The average runnable tasks show little activity

Average Runnable Tasks 1 min 5 min 15 min % of total

------------------------- ------------ ------------ ---------- ----------

ThreadPool : syb_default_pool

Global Queue 0.0 0.0 0.1 0.0 %

Engine 0 0.2 0.7 0.8 8.3 %

Engine 1 0.4 1.0 1.0 19.3 %

Engine 2 0.1 0.9 0.9 5.2 %

Engine 3 0.1 0.7 0.8 5.3 %

Engine 4 0.1 0.6 0.7 5.7 %

Engine 5 0.1 0.7 0.8 5.1 %

Engine 6 0.2 0.5 0.6 7.2 %

Engine 7 0.1 0.5 0.7 5.0 %

Engine 8 0.1 0.7 0.8 4.2 %

Engine 9 0.2 0.7 0.7 8.9 %

Engine 10 0.1 0.5 0.7 6.2 %

Engine 11 0.1 0.8 0.8 3.3 %

Engine 12 0.1 0.6 0.7 4.2 %

Engine 13 0.1 0.7 0.7 2.6 %

Engine 14 0.2 0.9 0.9 9.5 %

and the Thread utilisation shows this.

I can't see anything else running and the HK tasks should be pretty much idle.

Thread Utilization (OS %) User Busy System Busy Idle

------------------------- ------------ ------------ ----------

ThreadPool : syb_blocking_pool : no activity during sample

ThreadPool : syb_default_pool

Thread 6 (Engine 0) 2.8 % 0.1 % 97.1 %

Thread 7 (Engine 1) 6.8 % 0.5 % 92.7 %

Thread 8 (Engine 2) 6.9 % 0.3 % 92.8 %

Thread 9 (Engine 3) 8.0 % 0.1 % 91.9 %

Thread 10 (Engine 4) 8.7 % 0.4 % 90.9 %

Thread 11 (Engine 5) 3.8 % 0.1 % 96.1 %

Thread 12 (Engine 6) 15.7 % 0.9 % 83.4 %

Thread 13 (Engine 7) 8.2 % 0.4 % 91.4 %

Thread 14 (Engine 8) 17.0 % 0.9 % 82.1 %

Thread 15 (Engine 9) 17.6 % 0.4 % 82.0 %

Thread 16 (Engine 10) 19.8 % 1.0 % 79.2 %

Thread 17 (Engine 11) 13.3 % 0.8 % 85.9 %

Thread 18 (Engine 12) 24.8 % 1.4 % 73.8 %

Thread 19 (Engine 13) 18.5 % 0.7 % 80.8 %

Thread 20 (Engine 14) 7.2 % 0.3 % 92.5 %


ThreadPool : syb_system_pool

Thread 21 (NetController) 0.1 % 0.2 % 99.7 %

Thread 22 (DiskController) 3.2 % 1.2 % 95.6 %

The Disk and the Net Controller show its mostly idle. How does this ties in with the previous info showing IO Busy ?

Any idea if sysmon is correctly reporting IO ? Or if its correct how do I see what could be consuming the IO ?