Date: Mon, 17 Nov 2008 01:07:02 -0800 (PST) From: Won De Erick <won.derick@yahoo.com> To: Jeremy Chadwick <koitsu@FreeBSD.org> Cc: freebsd-hackers@freebsd.org, rwatson@freebsd.org Subject: Re: NET.ISR and CPU utilization performance w/ HP DL 585 using FreeBSD 7.1 Beta2 Message-ID: <245613.95922.qm@web45809.mail.sp1.yahoo.com>
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> ----- Original Message ---- > From: Won De Erick <won.derick@yahoo.com> > To: Jeremy Chadwick <koitsu@FreeBSD.org> > Cc: rwatson@freebsd.org; freebsd-hackers@freebsd.org > Sent: Sunday, November 16, 2008 7:18:46 PM > Subject: Re: NET.ISR and CPU utilization performance w/ HP DL 585 using FreeBSD 7.1 Beta2 > > > ----- Original Message ---- > > > From: Jeremy Chadwick <koitsu@FreeBSD.org> > > To: Won De Erick <won.derick@yahoo.com> > > Cc: rwatson@freebsd.org; freebsd-hackers@freebsd.org > > Sent: Saturday, November 15, 2008 10:16:31 PM > > Subject: Re: NET.ISR and CPU utilization performance w/ HP DL 585 using FreeBSD 7.1 Beta2 > > > > 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? > > The below result should be under scenario B above only. > > > > > > > - 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? > > With Intel Pro NIC ( 82571): > > When net.isr.direct=1, > > 49 root 1 -68 - 0K 16K CPU12 c 6:50 100.00% em0 taskq > 15 root 1 171 ki31 0K 16K CPU11 b 5:47 100.00% idle: cpu11 > 50 root 1 -68 - 0K 16K CPU13 d 6:15 86.96% em1 taskq > 25 root 1 171 ki31 0K 16K CPU1 1 9:27 79.79% idle: cpu1 > 28 root 1 -32 - 0K 16K WAIT 1 1:33 22.75% swi4: clock sio > 13 root 1 171 ki31 0K 16K RUN d 4:14 12.26% idle: cpu13 > 14 root 1 171 ki31 0K 16K RUN c 3:37 0.00% idle: cpu12 > > em0 and em1 have high CPU utilization, and with netstat, there were packet errors. > > # netstat -I em0 -w 1 -d > input (em0) output > packets errs bytes packets errs bytes colls drops > 15258 3066 22748316 18468 0 4886567 0 0 > 15461 3096 22783724 18379 0 5350130 0 0 > > > When net.isr.direct=0, > 12 root 1 171 ki31 0K 16K CPU14 e 22:28 100.00% idle: cpu14 > 20 root 1 171 ki31 0K 16K CPU6 6 24:32 97.85% idle: cpu6 > 25 root 1 171 ki31 0K 16K RUN 1 21:51 96.97% idle: cpu1 > 27 root 1 -44 - 0K 16K CPU2 2 5:12 91.55% swi1: net > 13 root 1 171 ki31 0K 16K CPU13 d 11:04 86.96% idle: cpu13 > 14 root 1 171 ki31 0K 16K CPU12 c 10:51 81.59% idle: cpu12 > 49 root 1 -68 - 0K 16K CPU12 c 13:48 22.17% em0 taskq > 24 root 1 171 ki31 0K 16K RUN 2 19:16 12.16% idle: cpu2 > 50 root 1 -68 - 0K 16K - d 13:34 11.87% em1 taskq > 28 root 1 -32 - 0K 16K WAIT 3 3:48 0.00% swi4: clock sio > > sw1:net is taking high CPU utilization this time, but without packet errors: > > # netstat -I em0 -w 1 -d > input (em0) output > packets errs bytes packets errs bytes colls drops > 4275 0 5528012 24878 0 24162198 0 0 > 4317 0 5585954 24880 0 24066583 0 0 > > > Is this related to the context switching in FreeBSD 7.x? I noticed that there were no significant difference in enabling and disabling net.isr.direct in FreeBSD > 6.2. > Also, is there any significance of enabling device polling? > > > > > -- > > | 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 | > > I compiled the following em driver for Intel NIC Pro (82571) w/ FreeBSD 7.1 Beta 2 on HPDL 585 machine having 16CPUs. http://people.yandex-team.ru/~wawa/ With net.isr.direct=1, I made some changes on kthreads(default=2) for em0 and em1's rx. dev.em.0.rx_kthreads: 6 .... dev.em.1.rx_kthreads: 6 With these settings, the result is: CPU: 0.0% user, 0.0% nice, 57.2% system, 3.6% interrupt, 39.2% idle Mem: 17M Active, 7228K Inact, 156M Wired, 76K Cache, 21M Buf, 31G Free Swap: 4096M Total, 4096M Free PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND 52 root 1 43 - 0K 16K CPU12 c 41:38 100.00% em0_rx_kthread_1 51 root 1 43 - 0K 16K CPU3 3 41:38 100.00% em0_rx_kthread_0 54 root 1 -68 - 0K 16K CPU2 2 39:39 100.00% em1_txcleaner 1283 root 1 43 - 0K 16K CPU1 1 38:55 100.00% em0_rx_kthread_3 1282 root 1 43 - 0K 16K CPU10 a 38:55 100.00% em0_rx_kthread_2 1344 root 1 43 - 0K 16K CPU9 9 25:51 100.00% em0_rx_kthread_5 1343 root 1 43 - 0K 16K CPU4 4 25:51 100.00% em0_rx_kthread_4 12 root 1 171 ki31 0K 16K CPU14 e 44:28 91.70% idle: cpu14 11 root 1 171 ki31 0K 16K CPU15 f 35:18 76.86% idle: cpu15 19 root 1 171 ki31 0K 16K RUN 7 24:56 70.46% idle: cpu7 20 root 1 171 ki31 0K 16K CPU6 6 35:23 69.38% idle: cpu6 15 root 1 171 ki31 0K 16K CPU11 b 34:33 65.97% idle: cpu11 18 root 1 171 ki31 0K 16K CPU8 8 40:24 64.45% idle: cpu8 13 root 1 171 ki31 0K 16K CPU13 d 42:07 61.96% idle: cpu13 21 root 1 171 ki31 0K 16K CPU5 5 21:35 58.79% idle: cpu5 28 root 1 -32 - 0K 16K WAIT 8 33:23 57.08% swi4: clock sio 25 root 1 171 ki31 0K 16K RUN 1 18:13 50.00% idle: cpu1 1347 root 1 43 - 0K 16K WAIT 5 10:48 44.68% em1_rx_kthread_5 55 root 1 43 - 0K 16K RUN 0 18:46 43.65% em1_rx_kthread_0 56 root 1 43 - 0K 16K WAIT 6 18:50 42.97% em1_rx_kthread_1 1280 root 1 43 - 0K 16K WAIT d 16:59 41.46% em1_rx_kthread_3 1279 root 1 43 - 0K 16K WAIT 7 17:00 41.06% em1_rx_kthread_2 1346 root 1 43 - 0K 16K WAIT b 10:47 40.77% em1_rx_kthread_4 26 root 1 171 ki31 0K 16K RUN 0 19:38 10.79% idle: cpu0 50 root 1 -68 - 0K 16K WAIT f 1:41 3.86% em0_txcleaner 24 root 1 171 ki31 0K 16K RUN 2 30:28 0.00% idle: cpu2 16 root 1 171 ki31 0K 16K RUN a 29:39 0.00% idle: cpu10 17 root 1 171 ki31 0K 16K RUN 9 27:08 0.00% idle: cpu9 14 root 1 171 ki31 0K 16K RUN c 21:58 0.00% idle: cpu12 23 root 1 171 ki31 0K 16K RUN 3 11:36 0.00% idle: cpu3 22 root 1 171 ki31 0K 16K RUN 4 10:24 0.00% idle: cpu4 27 root 1 -44 - 0K 16K WAIT 2 3:04 0.00% swi1: net I am happy to see that more processors are now working, but the kthreads are consuming HIGH CPU utilizations. is there any other things that I can look into and set to minimize CPU utilization for the threads? thanks, won
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