NET.ISR and CPU utilization performance w/ HP DL 585 using
FreeBSD 7.1 Beta2
Jeremy Chadwick
koitsu at FreeBSD.org
Sat Nov 15 06:16:33 PST 2008
On Sat, Nov 15, 2008 at 04:59:16AM -0800, Won De Erick wrote:
> Hello,
>
> I tested HP DL 585 (16 CPUs, w/ built-in Broadcom NICs) running FreeBSD 7.1 Beta2 under heavy network traffic (TCP).
>
> SCENARIO A : Bombarded w/ TCP traffic:
>
> When net.isr.direct=1,
>
> PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
> 52 root 1 -68 - 0K 16K CPU11 b 38:43 95.36% irq32: bce1
> 51 root 1 -68 - 0K 16K CPU10 a 25:50 85.16% irq31: bce0
> 16 root 1 171 ki31 0K 16K RUN a 65:39 15.97% idle: cpu10
> 28 root 1 -32 - 0K 16K WAIT 8 12:28 5.18% swi4: clock sio
> 15 root 1 171 ki31 0K 16K RUN b 52:46 3.76% idle: cpu11
> 45 root 1 -64 - 0K 16K WAIT 7 7:29 1.17% irq17: uhci0
> 47 root 1 -64 - 0K 16K WAIT 6 1:11 0.10% irq16: ciss0
> 27 root 1 -44 - 0K 16K WAIT 0 28:52 0.00% swi1: net
>
> When net.isr.direct=0,
>
> 16 root 1 171 ki31 0K 16K CPU10 a 106:46 92.58% idle: cpu10
> 19 root 1 171 ki31 0K 16K CPU7 7 133:37 89.16% idle: cpu7
> 27 root 1 -44 - 0K 16K WAIT 0 52:20 76.37% swi1: net
> 25 root 1 171 ki31 0K 16K RUN 1 132:30 70.26% idle: cpu1
> 26 root 1 171 ki31 0K 16K CPU0 0 111:58 64.36% idle: cpu0
> 15 root 1 171 ki31 0K 16K CPU11 b 81:09 57.76% idle: cpu11
> 52 root 1 -68 - 0K 16K WAIT b 64:00 42.97% irq32: bce1
> 51 root 1 -68 - 0K 16K WAIT a 38:22 12.26% irq31: bce0
> 45 root 1 -64 - 0K 16K WAIT 7 11:31 12.06% irq17: uhci0
> 47 root 1 -64 - 0K 16K WAIT 6 1:54 3.66% irq16: ciss0
> 28 root 1 -32 - 0K 16K WAIT 8 16:01 0.00% swi4: clock sio
>
> Overall CPU utilization has significantly dropped, but I noticed that swi1 has taken CPU0 with high utilization when the net.isr.direct=0.
> What does this mean?
>
> SCENARIO B : Bombarded w/ more TCP traffic:
>
> Worst thing, the box has become unresponsive (can't be PINGed, inaccessible through SSH) after more traffic was added retaining net.isr.direct=0.
> This is due maybe to the 100% utilization on CPU0 for sw1:net (see below result, first line). bce's and swi's seem to race each other based on the result when net.isr.direct=1, swi1 .
> The rest of the CPUs are sitting pretty (100% Idle). Can you shed some lights on this?
>
> When net.isr.direct=0:
> 27 root 1 -44 - 0K 16K CPU0 0 5:45 100.00% swi1: net
> 11 root 1 171 ki31 0K 16K CPU15 0 0:00 100.00% idle: cpu15
> 13 root 1 171 ki31 0K 16K CPU13 0 0:00 100.00% idle: cpu13
> 17 root 1 171 ki31 0K 16K CPU9 0 0:00 100.00% idle: cpu9
> 18 root 1 171 ki31 0K 16K CPU8 0 0:00 100.00% idle: cpu8
> 21 root 1 171 ki31 0K 16K CPU5 5 146:17 99.17% idle: cpu5
> 22 root 1 171 ki31 0K 16K CPU4 4 146:17 99.07% idle: cpu4
> 14 root 1 171 ki31 0K 16K CPU12 0 0:00 99.07% idle: cpu12
> 16 root 1 171 ki31 0K 16K CPU10 a 109:33 98.88% idle: cpu10
> 15 root 1 171 ki31 0K 16K CPU11 b 86:36 93.55% idle: cpu11
> 52 root 1 -68 - 0K 16K WAIT b 59:42 13.87% irq32: bce1
>
> When net.isr.direct=1,
> 52 root 1 -68 - 0K 16K CPU11 b 55:04 97.66% irq32: bce1
> 51 root 1 -68 - 0K 16K CPU10 a 33:52 73.88% irq31: bce0
> 16 root 1 171 ki31 0K 16K RUN a 102:42 26.86% idle: cpu10
> 15 root 1 171 ki31 0K 16K RUN b 81:20 3.17% idle: cpu11
> 28 root 1 -32 - 0K 16K WAIT e 13:40 0.00% swi4: clock sio
>
> With regards to bandwidth in all scenarios above, the result is extremely low (expected is several hundred Mb/s). Why?
>
> - iface Rx Tx Total
> ==============================================================================
> bce0: 4.69 Mb/s 10.49 Mb/s 15.18 Mb/s
> bce1: 20.66 Mb/s 4.68 Mb/s 25.34 Mb/s
> lo0: 0.00 b/s 0.00 b/s 0.00 b/s
> ------------------------------------------------------------------------------
> total: 25.35 Mb/s 15.17 Mb/s 40.52 Mb/s
>
>
> Thanks,
>
> Won
And does this behaviour change if you use some other brand of NIC?
--
| Jeremy Chadwick jdc at parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
| Making life hard for others since 1977. PGP: 4BD6C0CB |
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