* Poor UDP performance using 2.6.21-rc5-rt5
@ 2007-04-01 19:15 Dave Sperry
2007-04-01 20:07 ` Nivedita Singhvi
2007-04-02 7:21 ` Ingo Molnar
0 siblings, 2 replies; 16+ messages in thread
From: Dave Sperry @ 2007-04-01 19:15 UTC (permalink / raw)
To: linux-rt-users; +Cc: linux-kernel
Hi
I have a dual core Opteron machine that exhibits poor UDP performance
(RT consumes more than 2X cpu) with the 2.6.21-rc5-rt5 as compared to
2.6.21-rc5. Top shows the IRQ handler consuming a lot of CPU.
The mother board is a Supermicro H8DME-2 with one dual core Opteron
installed. The networking is provided by the on board nVidia MCP55Pro chip.
The RT test is done using netperf 2.4.3 with the server on an IBM LS20
blade running RHEL4U2 and the Supermicro running netperf under RHEL5
with 2.6.21-rc5-rt5.
The Non-RT test was done on the exact same setup except 2.6.21-rc5-rt5
was loaded on the SuperMicro board.
Cyclesoak was used to measure CPU utilization in all cases.
Here are the RT results
########################################################3
## 2.6.21-rc5-rt5
#######################################################
$ !netper
netperf -l 100 -H 192.168.70.11 -t UDP_STREAM -- -m 1025
UDP UNIDIRECTIONAL SEND TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
192.168.70.11 (192.168.70.11) port 0 AF_INET
Socket Message Elapsed Messages
Size Size Time Okay Errors Throughput
bytes bytes secs # # 10^6bits/sec
126976 1025 100.00 8676376 0 711.46
135168 100.00 8676376 711.46
########## cyclesoak during test
$ ./cyclesoak
using 2 CPUs
System load: -0.1%
System load: 40.5%
System load: 51.6%
System load: 51.5%
System load: 50.9%
System load: 50.7%
System load: 50.8%
System load: 50.7%
System load: 50.6%
######## top during test
top - 13:26:48 up 8 min, 4 users, load average: 1.74, 0.46, 0.15
Tasks: 149 total, 4 running, 145 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.7%us, 16.8%sy, 50.6%ni, 0.0%id, 0.0%wa, 25.6%hi, 6.3%si,
0.0%st
Mem: 2035444k total, 465888k used, 1569556k free, 28840k buffers
Swap: 3068372k total, 0k used, 3068372k free, 318668k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3865 eadi 39 19 6804 1164 108 R 100 0.1 0:38.25 cyclesoak
2715 root -51 -5 0 0 0 S 51 0.0 0:09.52 IRQ-8406
3867 eadi 25 0 6440 632 480 R 34 0.0 0:06.03 netperf
19 root -51 0 0 0 0 S 13 0.0 0:02.33 softirq-net-tx/
3866 eadi 39 19 6804 1164 108 R 1 0.1 0:20.47 cyclesoak
3167 root 25 0 29888 1180 888 S 0 0.1 0:00.93 automount
3861 eadi 15 0 12712 1076 788 R 0 0.1 0:00.19 top
1 root 18 0 10308 668 552 S 0 0.0 0:00.67 init
2 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0
3 root RT 0 0 0 0 S 0 0.0 0:00.00 posix_cpu_timer
4 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-high/0
5 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-timer/0
6 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-net-tx/
7 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-net-rx/
8 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-block/0
########################
The baseline results:
RHEL5 with 2.6.21-rc5 kernel
##############################
$ netperf -l 100 -H 192.168.70.11 -t UDP_STREAM -- -m 1025
UDP UNIDIRECTIONAL SEND TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
192.168.70.11 (192.168.70.11) port 0 AF_INET
Socket Message Elapsed Messages
Size Size Time Okay Errors Throughput
bytes bytes secs # # 10^6bits/sec
126976 1025 100.00 11405485 0 935.24
135168 100.00 11405485 935.24
#######################################
$ ./cyclesoak
using 2 CPUs
System load: 7.6%
System load: 29.6%
System load: 29.6%
System load: 28.9%
System load: 24.9%
System load: 25.0%
System load: 24.8%
System load: 24.9%
#######################################
top:top - 13:52:22 up 10 min, 6 users, load average: 1.46, 0.43, 0.17
Tasks: 118 total, 4 running, 114 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.5%us, 9.8%sy, 75.7%ni, 0.0%id, 0.0%wa, 5.8%hi, 8.1%si,
0.0%st
Mem: 2057200k total, 459128k used, 1598072k free, 29020k buffers
Swap: 3068372k total, 0k used, 3068372k free, 318968k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3882 eadi 39 19 6804 1164 108 R 100 0.1 0:52.11 cyclesoak
3881 eadi 39 19 6804 1164 108 R 65 0.1 0:38.47 cyclesoak
3883 eadi 15 0 6436 632 480 R 35 0.0 0:18.26 netperf
3879 eadi 15 0 12580 1052 788 R 0 0.1 0:00.15 top
1 root 18 0 10308 664 552 S 0 0.0 0:00.48 init
2 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0
3 root 34 19 0 0 0 S 0 0.0 0:00.01 ksoftirqd/0
4 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/0
5 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/1
6 root 34 19 0 0 0 S 0 0.0 0:00.00 ksoftirqd/1
Any thoughts on how to fix this?
Thanks,
-Dave
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-01 19:15 Poor UDP performance using 2.6.21-rc5-rt5 Dave Sperry
@ 2007-04-01 20:07 ` Nivedita Singhvi
2007-04-01 22:00 ` Dave Sperry
2007-04-02 5:55 ` Ingo Molnar
2007-04-02 7:21 ` Ingo Molnar
1 sibling, 2 replies; 16+ messages in thread
From: Nivedita Singhvi @ 2007-04-01 20:07 UTC (permalink / raw)
To: Dave Sperry; +Cc: linux-rt-users, linux-kernel, netdev
Dave Sperry wrote:
> Hi
(adding netdev to cc list)
> I have a dual core Opteron machine that exhibits poor UDP performance
> (RT consumes more than 2X cpu) with the 2.6.21-rc5-rt5 as compared to
> 2.6.21-rc5. Top shows the IRQ handler consuming a lot of CPU.
Dave, any chance you've got oprofile working on the -rt5?
And I'm assuming nothing very different in the stats or errors
through both runs?
thanks,
Nivedita
> The mother board is a Supermicro H8DME-2 with one dual core Opteron
> installed. The networking is provided by the on board nVidia MCP55Pro chip.
>
> The RT test is done using netperf 2.4.3 with the server on an IBM LS20
> blade running RHEL4U2 and the Supermicro running netperf under RHEL5
> with 2.6.21-rc5-rt5.
> The Non-RT test was done on the exact same setup except 2.6.21-rc5-rt5
> was loaded on the SuperMicro board.
>
> Cyclesoak was used to measure CPU utilization in all cases.
>
>
>
> Here are the RT results
> ########################################################3
> ## 2.6.21-rc5-rt5
> #######################################################
> $ !netper
> netperf -l 100 -H 192.168.70.11 -t UDP_STREAM -- -m 1025
> UDP UNIDIRECTIONAL SEND TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
> 192.168.70.11 (192.168.70.11) port 0 AF_INET
> Socket Message Elapsed Messages
> Size Size Time Okay Errors Throughput
> bytes bytes secs # # 10^6bits/sec
>
> 126976 1025 100.00 8676376 0 711.46
> 135168 100.00 8676376 711.46
>
> ########## cyclesoak during test
> $ ./cyclesoak
> using 2 CPUs
> System load: -0.1%
> System load: 40.5%
> System load: 51.6%
> System load: 51.5%
> System load: 50.9%
> System load: 50.7%
> System load: 50.8%
> System load: 50.7%
> System load: 50.6%
>
> ######## top during test
> top - 13:26:48 up 8 min, 4 users, load average: 1.74, 0.46, 0.15
> Tasks: 149 total, 4 running, 145 sleeping, 0 stopped, 0 zombie
> Cpu(s): 0.7%us, 16.8%sy, 50.6%ni, 0.0%id, 0.0%wa, 25.6%hi, 6.3%si,
> 0.0%st
> Mem: 2035444k total, 465888k used, 1569556k free, 28840k buffers
> Swap: 3068372k total, 0k used, 3068372k free, 318668k cached
>
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 3865 eadi 39 19 6804 1164 108 R 100 0.1 0:38.25 cyclesoak
> 2715 root -51 -5 0 0 0 S 51 0.0 0:09.52 IRQ-8406
> 3867 eadi 25 0 6440 632 480 R 34 0.0 0:06.03
> netperf 19 root -51 0 0 0 0 S 13 0.0
> 0:02.33 softirq-net-tx/
> 3866 eadi 39 19 6804 1164 108 R 1 0.1 0:20.47 cyclesoak
> 3167 root 25 0 29888 1180 888 S 0 0.1 0:00.93 automount
> 3861 eadi 15 0 12712 1076 788 R 0 0.1 0:00.19 top
> 1 root 18 0 10308 668 552 S 0 0.0 0:00.67 init
> 2 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0
> 3 root RT 0 0 0 0 S 0 0.0 0:00.00 posix_cpu_timer
> 4 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-high/0
> 5 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-timer/0
> 6 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-net-tx/
> 7 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-net-rx/
> 8 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-block/0
>
> ########################
> The baseline results:
> RHEL5 with 2.6.21-rc5 kernel
> ##############################
>
> $ netperf -l 100 -H 192.168.70.11 -t UDP_STREAM -- -m 1025
>
> UDP UNIDIRECTIONAL SEND TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
> 192.168.70.11 (192.168.70.11) port 0 AF_INET
> Socket Message Elapsed Messages
> Size Size Time Okay Errors Throughput
> bytes bytes secs # # 10^6bits/sec
>
> 126976 1025 100.00 11405485 0 935.24
> 135168 100.00 11405485 935.24
>
> #######################################
> $ ./cyclesoak
> using 2 CPUs
> System load: 7.6%
> System load: 29.6%
> System load: 29.6%
> System load: 28.9%
> System load: 24.9%
> System load: 25.0%
> System load: 24.8%
> System load: 24.9%
>
> #######################################
> top:top - 13:52:22 up 10 min, 6 users, load average: 1.46, 0.43, 0.17
> Tasks: 118 total, 4 running, 114 sleeping, 0 stopped, 0 zombie
> Cpu(s): 0.5%us, 9.8%sy, 75.7%ni, 0.0%id, 0.0%wa, 5.8%hi, 8.1%si,
> 0.0%st
> Mem: 2057200k total, 459128k used, 1598072k free, 29020k buffers
> Swap: 3068372k total, 0k used, 3068372k free, 318968k cached
>
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 3882 eadi 39 19 6804 1164 108 R 100 0.1 0:52.11 cyclesoak
> 3881 eadi 39 19 6804 1164 108 R 65 0.1 0:38.47 cyclesoak
> 3883 eadi 15 0 6436 632 480 R 35 0.0 0:18.26 netperf
> 3879 eadi 15 0 12580 1052 788 R 0 0.1 0:00.15 top
> 1 root 18 0 10308 664 552 S 0 0.0 0:00.48 init
> 2 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0
> 3 root 34 19 0 0 0 S 0 0.0 0:00.01 ksoftirqd/0
> 4 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/0
> 5 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/1
> 6 root 34 19 0 0 0 S 0 0.0 0:00.00 ksoftirqd/1
>
> Any thoughts on how to fix this?
>
> Thanks,
> -Dave
>
>
>
>
>
>
>
>
>
>
>
> -
> To unsubscribe from this list: send the line "unsubscribe
> linux-rt-users" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-01 20:07 ` Nivedita Singhvi
@ 2007-04-01 22:00 ` Dave Sperry
2007-04-02 5:55 ` Ingo Molnar
1 sibling, 0 replies; 16+ messages in thread
From: Dave Sperry @ 2007-04-01 22:00 UTC (permalink / raw)
To: Nivedita Singhvi; +Cc: linux-rt-users, linux-kernel, netdev
Nivedita Singhvi wrote:
> Dave Sperry wrote:
>> Hi
>
> (adding netdev to cc list)
>
>> I have a dual core Opteron machine that exhibits poor UDP performance
>> (RT consumes more than 2X cpu) with the 2.6.21-rc5-rt5 as compared to
>> 2.6.21-rc5. Top shows the IRQ handler consuming a lot of CPU.
>
> Dave, any chance you've got oprofile working on the -rt5?
Yes, I have a opreport from about 15 seconds in the middle of the test
below is the top of the report.
> And I'm assuming nothing very different in the stats or errors
> through both runs?
correct. no errors, the throughput in the RT was less, I assume it was
CPU bound.
Thanks
Dave.
CPU: AMD64 processors, speed 2211.36 MHz (estimated)
Counted CPU_CLK_UNHALTED events (Cycles outside of halt state) with a
unit mask of 0x00 (No unit mask) count 100000
samples % image name app name
symbol name
16375 13.2965 vmlinux vmlinux
__sched_text_start
7820 6.3498 vmlinux vmlinux
copy_user_generic_string
7019 5.6994 forcedeth.ko forcedeth
nv_start_xmit_optimized
6733 5.4672 forcedeth.ko forcedeth
nv_nic_irq_optimized
6572 5.3365 vmlinux vmlinux
__switch_to
6440 5.2293 vmlinux vmlinux
pfifo_fast_dequeue
5796 4.7063 vmlinux vmlinux
handle_IRQ_event
4557 3.7003 vmlinux vmlinux
ip_output
4452 3.6150 vmlinux vmlinux
try_to_wake_up
3698 3.0028 forcedeth.ko forcedeth
nv_tx_done_optimized
3599 2.9224 vmlinux vmlinux
udp_sendmsg
3424 2.7803 vmlinux vmlinux
reschedule_interrupt
3308 2.6861 vmlinux vmlinux
IRQ0xc1_interrupt
3095 2.5131 vmlinux vmlinux
ip_append_data
2835 2.3020 vmlinux vmlinux
kmem_cache_free
2274 1.8465 vmlinux vmlinux
thread_return
2080 1.6890 vmlinux vmlinux kfree
1864 1.5136 vmlinux vmlinux
dev_queue_xmit
1862 1.5119 vmlinux vmlinux
sock_sendmsg
1606 1.3041 libc-2.5.so libc-2.5.so
__sendto_nocancel
1464 1.1888 vmlinux vmlinux memset_c
1439 1.1685 vmlinux vmlinux
__ip_route_output_key
1344 1.0913 vmlinux vmlinux schedule
1167 0.9476 oprofiled oprofiled (no
symbols)
1010 0.8201 vmlinux vmlinux
sock_wfree
998 0.8104 vmlinux vmlinux memcpy_c
910 0.7389 vmlinux vmlinux
__might_sleep
880 0.7146 vmlinux vmlinux
system_call
735 0.5968 vmlinux vmlinux
preempt_schedule_irq
726 0.5895 vmlinux vmlinux
__bitmap_empty
722 0.5863 vmlinux vmlinux
atomic_notifier_call_chain
701 0.5692 vmlinux vmlinux
current_kernel_time
681 0.5530 vmlinux vmlinux
release_sock
663 0.5384 vmlinux vmlinux
rt_hash_code
660 0.5359 vmlinux vmlinux
pfifo_fast_enqueue
618 0.5018 vmlinux vmlinux cpu_idle
617 0.5010 vmlinux vmlinux
kthread_should_stop
601 0.4880 vmlinux vmlinux
__alloc_skb
591 0.4799 oprofile oprofile (no
symbols)
551 0.4474 vmlinux vmlinux
__wake_up
505 0.4101 vmlinux vmlinux
kfree_skbmem
494 0.4011 vmlinux vmlinux
inet_sendmsg
450 0.3654 netperf netperf
send_udp_stream
448 0.3638 vmlinux vmlinux
__kfree_skb
391 0.3175 vmlinux vmlinux
common_interrupt
366 0.2972 vmlinux vmlinux
find_next_bit
346 0.2810 vmlinux vmlinux
ret_from_intr
343 0.2785 vmlinux vmlinux
fget_light
333 0.2704 vmlinux vmlinux
retint_swapgs
327 0.2655 vmlinux vmlinux
exit_intr
312 0.2533 vmlinux vmlinux tracesys
309 0.2509 vmlinux vmlinux
rt_spin_lock_slowlock
306 0.2485 vmlinux vmlinux
cond_resched_softirq_context
303 0.2460 vmlinux vmlinux
retint_kernel
296 0.2404 vmlinux vmlinux
cond_resched
256 0.2079 bash bash (no
symbols)
252 0.2046 vmlinux vmlinux
preempt_schedule
248 0.2014 vmlinux vmlinux
int_ret_from_sys_call
242 0.1965 vmlinux vmlinux
restore_args
226 0.1835 libc-2.5.so libc-2.5.so sendto
199 0.1616 vmlinux vmlinux
copy_from_user
181 0.1470 vmlinux vmlinux
notifier_call_chain
165 0.1340 forcedeth.ko forcedeth
nv_rx_process_optimized
163 0.1324 vmlinux vmlinux
int_very_careful
139 0.1129 libc-2.5.so libc-2.5.so
__gconv_transform_utf8_internal
114 0.0926 vmlinux vmlinux
__handle_mm_fault
114 0.0926 vmlinux vmlinux
get_task_mm
104 0.0844 vmlinux vmlinux
find_first_bit
103 0.0836 vmlinux vmlinux
int_restore_rest
96 0.0780 vmlinux vmlinux
dummy_socket_sendmsg
87 0.0706 vmlinux vmlinux
copy_page_c
83 0.0674 jbd jbd (no
symbols)
79 0.0641 vmlinux vmlinux
clear_page_c
77 0.0625 vmlinux vmlinux
exit_idle
76 0.0617 libc-2.5.so libc-2.5.so mbrtowc
72 0.0585 vmlinux vmlinux
apic_timer_interrupt
67 0.0544 vmlinux vmlinux __delay
66 0.0536 vmlinux vmlinux
page_fault
65 0.0528 vmlinux vmlinux
unmap_vmas
62 0.0503 vmlinux vmlinux
rt_spin_lock_slowunlock
55 0.0447 ext3 ext3 (no
symbols)
55 0.0447 vmlinux vmlinux
__spin_lock_irqsave
53 0.0430 vmlinux vmlinux
rt_read_lock
50 0.0406 vmlinux vmlinux
int_with_check
44 0.0357 vmlinux vmlinux
rt_read_unlock
41 0.0333 libc-2.5.so libc-2.5.so
_int_malloc
40 0.0325 vmlinux vmlinux
enter_idle
36 0.0292 vmlinux vmlinux
find_get_page
33 0.0268 vmlinux vmlinux
do_page_fault
32 0.0260 libc-2.5.so libc-2.5.so _dl_addr
29 0.0235 vmlinux vmlinux
__d_lookup
28 0.0227 vmlinux vmlinux
copy_page_range
26 0.0211 libc-2.5.so libc-2.5.so
_int_free
24 0.0195 vmlinux vmlinux
__spin_unlock_irqrestore
24 0.0195 vmlinux vmlinux
iret_label
24 0.0195 vmlinux vmlinux memcpy
24 0.0195 vmlinux vmlinux
vm_normal_page
23 0.0187 vmlinux vmlinux
kmem_cache_alloc
23 0.0187 vmlinux vmlinux rb_erase
23 0.0187 vmlinux vmlinux
retint_restore_args
21 0.0171 vmlinux vmlinux rb_first
19 0.0154 vmlinux vmlinux
__link_path_walk
18 0.0146 libc-2.5.so libc-2.5.so strlen
18 0.0146 vmlinux vmlinux
do_wp_page
17 0.0138 vmlinux vmlinux find_vma
16 0.0130 libpthread-2.5.so libpthread-2.5.so
pthread_cond_timedwait@@GLIBC_2.3.2
16 0.0130 vmlinux vmlinux
flush_tlb_page
15 0.0122 vmlinux vmlinux
rb_insert_color
15 0.0122 vmlinux vmlinux
rt_mutex_lock
14 0.0114 libc-2.5.so libc-2.5.so
_dl_mcount_wrapper_check
14 0.0114 netperf netperf .plt
13 0.0106 vmlinux vmlinux
cache_alloc_refill
13 0.0106 vmlinux vmlinux
get_page_from_freelist
12 0.0097 libc-2.5.so libc-2.5.so malloc
12 0.0097 vmlinux vmlinux
copy_process
12 0.0097 vmlinux vmlinux
hrtimer_run_queues
12 0.0097 vmlinux vmlinux
release_pages
11 0.0089 ld-2.5.so ld-2.5.so
_dl_cache_libcmp
11 0.0089 libc-2.5.so libc-2.5.so free
11 0.0089 vmlinux vmlinux memset
10 0.0081 libc-2.5.so libc-2.5.so strcpy
10 0.0081 libcrypto.so.0.9.8b libcrypto.so.0.9.8b (no
symbols)
10 0.0081 libglib-2.0.so.0.1200.3 libglib-2.0.so.0.1200.3 (no
symbols)
10 0.0081 vmlinux vmlinux
__find_get_block
9 0.0073 ehci_hcd ehci_hcd (no
symbols)
9 0.0073 vmlinux vmlinux
do_lookup
9 0.0073 vmlinux vmlinux
error_exit
9 0.0073 vmlinux vmlinux
lock_timer_base
9 0.0073 vmlinux vmlinux rb_next
8 0.0065 gawk gawk (no
symbols)
8 0.0065 libc-2.5.so libc-2.5.so
sigprocmask
8 0.0065 libpython2.4.so.1.0 libpython2.4.so.1.0 (no
symbols)
8 0.0065 vmlinux vmlinux
__strncpy_from_user
8 0.0065 vmlinux vmlinux
__strnlen_user
8 0.0065 vmlinux vmlinux
do_mmap_pgoff
8 0.0065 vmlinux vmlinux dput
7 0.0057 libc-2.5.so libc-2.5.so strchr
7 0.0057 libc-2.5.so libc-2.5.so strncpy
7 0.0057 sshd sshd (no
symbols)
7 0.0057 vmlinux vmlinux
call_softirq
7 0.0057 vmlinux vmlinux
filemap_nopage
7 0.0057 vmlinux vmlinux
rt_mutex_trylock
6 0.0049 ld-2.5.so ld-2.5.so
_dl_map_object_from_fd
6 0.0049 vmlinux vmlinux
IRQ0xb9_interrupt
6 0.0049 vmlinux vmlinux
find_vma_prepare
6 0.0049 vmlinux vmlinux
free_hot_cold_page
6 0.0049 vmlinux vmlinux
free_pgtables
6 0.0049 vmlinux vmlinux
lru_cache_add_active
6 0.0049 vmlinux vmlinux number
6 0.0049 vmlinux vmlinux
page_remove_rmap
6 0.0049 vmlinux vmlinux
retint_careful
6 0.0049 vmlinux vmlinux
rt_mutex_unlock
6 0.0049 vmlinux vmlinux
set_normalized_timespec
5 0.0041 grep grep (no
symbols)
5 0.0041 ld-2.5.so ld-2.5.so dl_main
5 0.0041 libc-2.5.so libc-2.5.so memcpy
5 0.0041 libc-2.5.so libc-2.5.so strcmp
5 0.0041 libpthread-2.5.so libpthread-2.5.so
__lll_mutex_unlock_wake
5 0.0041 scsi_mod scsi_mod (no
symbols)
5 0.0041 vmlinux vmlinux
__pagevec_lru_add_active
5 0.0041 vmlinux vmlinux
anon_vma_prepare
5 0.0041 vmlinux vmlinux
anon_vma_unlink
5 0.0041 vmlinux vmlinux
do_path_lookup
5 0.0041 vmlinux vmlinux
free_pages_and_swap_cache
5 0.0041 vmlinux vmlinux
page_add_file_rmap
4 0.0032 forcedeth.ko forcedeth
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1 8.1e-04 dirname dirname (no
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__GI___fxstat
1
>
> thanks,
> Nivedita
>
>> The mother board is a Supermicro H8DME-2 with one dual core Opteron
>> installed. The networking is provided by the on board nVidia MCP55Pro
>> chip.
>>
>> The RT test is done using netperf 2.4.3 with the server on an IBM
>> LS20 blade running RHEL4U2 and the Supermicro running netperf under
>> RHEL5 with 2.6.21-rc5-rt5.
>> The Non-RT test was done on the exact same setup except
>> 2.6.21-rc5-rt5 was loaded on the SuperMicro board.
>>
>> Cyclesoak was used to measure CPU utilization in all cases.
>>
>>
>>
>> Here are the RT results
>> ########################################################3
>> ## 2.6.21-rc5-rt5
>> #######################################################
>> $ !netper
>> netperf -l 100 -H 192.168.70.11 -t UDP_STREAM -- -m 1025
>> UDP UNIDIRECTIONAL SEND TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
>> 192.168.70.11 (192.168.70.11) port 0 AF_INET
>> Socket Message Elapsed Messages
>> Size Size Time Okay Errors Throughput
>> bytes bytes secs # # 10^6bits/sec
>>
>> 126976 1025 100.00 8676376 0 711.46
>> 135168 100.00 8676376 711.46
>>
>> ########## cyclesoak during test
>> $ ./cyclesoak
>> using 2 CPUs
>> System load: -0.1%
>> System load: 40.5%
>> System load: 51.6%
>> System load: 51.5%
>> System load: 50.9%
>> System load: 50.7%
>> System load: 50.8%
>> System load: 50.7%
>> System load: 50.6%
>>
>> ######## top during test
>> top - 13:26:48 up 8 min, 4 users, load average: 1.74, 0.46, 0.15
>> Tasks: 149 total, 4 running, 145 sleeping, 0 stopped, 0 zombie
>> Cpu(s): 0.7%us, 16.8%sy, 50.6%ni, 0.0%id, 0.0%wa, 25.6%hi,
>> 6.3%si, 0.0%st
>> Mem: 2035444k total, 465888k used, 1569556k free, 28840k buffers
>> Swap: 3068372k total, 0k used, 3068372k free, 318668k cached
>>
>> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
>> 3865 eadi 39 19 6804 1164 108 R 100 0.1 0:38.25 cyclesoak
>> 2715 root -51 -5 0 0 0 S 51 0.0 0:09.52 IRQ-8406
>> 3867 eadi 25 0 6440 632 480 R 34 0.0 0:06.03
>> netperf 19 root -51 0 0 0 0 S 13 0.0
>> 0:02.33 softirq-net-tx/
>> 3866 eadi 39 19 6804 1164 108 R 1 0.1 0:20.47 cyclesoak
>> 3167 root 25 0 29888 1180 888 S 0 0.1 0:00.93 automount
>> 3861 eadi 15 0 12712 1076 788 R 0 0.1 0:00.19 top
>> 1 root 18 0 10308 668 552 S 0 0.0 0:00.67
>> init 2 root RT 0 0 0 0 S 0 0.0 0:00.00
>> migration/0 3 root RT 0 0 0 0 S 0 0.0
>> 0:00.00 posix_cpu_timer
>> 4 root -51 0 0 0 0 S 0 0.0 0:00.00
>> softirq-high/0
>> 5 root -51 0 0 0 0 S 0 0.0 0:00.00
>> softirq-timer/0
>> 6 root -51 0 0 0 0 S 0 0.0 0:00.00
>> softirq-net-tx/
>> 7 root -51 0 0 0 0 S 0 0.0 0:00.00
>> softirq-net-rx/
>> 8 root -51 0 0 0 0 S 0 0.0 0:00.00
>> softirq-block/0
>>
>> ########################
>> The baseline results:
>> RHEL5 with 2.6.21-rc5 kernel
>> ##############################
>>
>> $ netperf -l 100 -H 192.168.70.11 -t UDP_STREAM -- -m 1025
>>
>> UDP UNIDIRECTIONAL SEND TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
>> 192.168.70.11 (192.168.70.11) port 0 AF_INET
>> Socket Message Elapsed Messages
>> Size Size Time Okay Errors Throughput
>> bytes bytes secs # # 10^6bits/sec
>>
>> 126976 1025 100.00 11405485 0 935.24
>> 135168 100.00 11405485 935.24
>>
>> #######################################
>> $ ./cyclesoak
>> using 2 CPUs
>> System load: 7.6%
>> System load: 29.6%
>> System load: 29.6%
>> System load: 28.9%
>> System load: 24.9%
>> System load: 25.0%
>> System load: 24.8%
>> System load: 24.9%
>>
>> #######################################
>> top:top - 13:52:22 up 10 min, 6 users, load average: 1.46, 0.43, 0.17
>> Tasks: 118 total, 4 running, 114 sleeping, 0 stopped, 0 zombie
>> Cpu(s): 0.5%us, 9.8%sy, 75.7%ni, 0.0%id, 0.0%wa, 5.8%hi,
>> 8.1%si, 0.0%st
>> Mem: 2057200k total, 459128k used, 1598072k free, 29020k buffers
>> Swap: 3068372k total, 0k used, 3068372k free, 318968k cached
>>
>> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
>> 3882 eadi 39 19 6804 1164 108 R 100 0.1 0:52.11 cyclesoak
>> 3881 eadi 39 19 6804 1164 108 R 65 0.1 0:38.47 cyclesoak
>> 3883 eadi 15 0 6436 632 480 R 35 0.0 0:18.26 netperf
>> 3879 eadi 15 0 12580 1052 788 R 0 0.1 0:00.15 top
>> 1 root 18 0 10308 664 552 S 0 0.0 0:00.48
>> init 2 root RT 0 0 0 0 S 0 0.0 0:00.00
>> migration/0
>> 3 root 34 19 0 0 0 S 0 0.0 0:00.01 ksoftirqd/0
>> 4 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/0
>> 5 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/1
>> 6 root 34 19 0 0 0 S 0 0.0 0:00.00 ksoftirqd/1
>>
>> Any thoughts on how to fix this?
>>
>> Thanks,
>> -Dave
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> -
>> To unsubscribe from this list: send the line "unsubscribe
>> linux-rt-users" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-01 20:07 ` Nivedita Singhvi
2007-04-01 22:00 ` Dave Sperry
@ 2007-04-02 5:55 ` Ingo Molnar
2007-04-02 6:30 ` Ingo Molnar
1 sibling, 1 reply; 16+ messages in thread
From: Ingo Molnar @ 2007-04-02 5:55 UTC (permalink / raw)
To: Nivedita Singhvi; +Cc: Dave Sperry, linux-rt-users, linux-kernel, netdev
* Nivedita Singhvi <niv@us.ibm.com> wrote:
> Dave Sperry wrote:
> >Hi
>
> (adding netdev to cc list)
in general (except of course those netdev folks that are interested in
-rt+networking performance matters) i'd suggest we analyze this in an
-rt specific way - netdev shouldnt have to bother about this.
> And I'm assuming nothing very different in the stats or errors through
> both runs?
one thing to check would be whether both kernels use the same
clocksource, via:
cat /sys/devices/system/clocksource/clocksource0/current_clocksource
but at first sight there's no clocksource related overhead in the
oprofile.
Ingo
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-02 5:55 ` Ingo Molnar
@ 2007-04-02 6:30 ` Ingo Molnar
0 siblings, 0 replies; 16+ messages in thread
From: Ingo Molnar @ 2007-04-02 6:30 UTC (permalink / raw)
To: Nivedita Singhvi; +Cc: Dave Sperry, linux-rt-users, linux-kernel, netdev
* Ingo Molnar <mingo@elte.hu> wrote:
> one thing to check would be whether both kernels use the same
> clocksource, via:
>
> cat /sys/devices/system/clocksource/clocksource0/current_clocksource
>
> but at first sight there's no clocksource related overhead in the
> oprofile.
i've started a similar netperf test and clocksource overhead dominates
the profile:
5553 handle_fasteoi_irq 26.1934
5940 nv_start_xmit_optimized 6.6892
6014 ack_ioapic_quirk_irq 44.5481
7591 mask_IO_APIC_irq 154.9184
8155 __copy_from_user_ll 37.4083
13371 io_apic_base 417.8438
13565 get_next_timer_interrupt 29.7478
13966 __modify_IO_APIC_irq 151.8043
14213 do_irqd 22.7045
17834 unmask_IO_APIC_irq 424.6190
20503 __schedule 6.4455
48456 cpu_idle 180.8060
170001 acpi_pm_read 8947.4211
517107 total 0.1566
acpi_pm_read() amounts to 32% overhead!
i'm not sure why the oprofile results show no clocksource overhead - the
-rt kernel typically uses the pm-timer on Opterons.
to get more comparable results, boot the vanilla kernel with the
"apicpmtimer" boot option, and/or do this after bootup:
echo acpi_pm > /sys/devices/system/clocksource/clocksource0/current_clocksource
Ingo
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-01 19:15 Poor UDP performance using 2.6.21-rc5-rt5 Dave Sperry
2007-04-01 20:07 ` Nivedita Singhvi
@ 2007-04-02 7:21 ` Ingo Molnar
2007-04-02 8:17 ` Dave Sperry
1 sibling, 1 reply; 16+ messages in thread
From: Ingo Molnar @ 2007-04-02 7:21 UTC (permalink / raw)
To: Dave Sperry; +Cc: linux-rt-users, linux-kernel
* Dave Sperry <dave_sperry@ieee.org> wrote:
> I have a dual core Opteron machine that exhibits poor UDP performance
> (RT consumes more than 2X cpu) with the 2.6.21-rc5-rt5 as compared to
> 2.6.21-rc5. Top shows the IRQ handler consuming a lot of CPU.
update: even with acpi_pm clocksource on vanilla i can reproduce similar
overhead using netperf.
Ingo
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-02 7:21 ` Ingo Molnar
@ 2007-04-02 8:17 ` Dave Sperry
2007-04-02 9:37 ` Ingo Molnar
0 siblings, 1 reply; 16+ messages in thread
From: Dave Sperry @ 2007-04-02 8:17 UTC (permalink / raw)
To: Ingo Molnar; +Cc: linux-rt-users, linux-kernel
Ingo Molnar wrote:
> * Dave Sperry <dave_sperry@ieee.org> wrote:
>
>> I have a dual core Opteron machine that exhibits poor UDP performance
>> (RT consumes more than 2X cpu) with the 2.6.21-rc5-rt5 as compared to
>> 2.6.21-rc5. Top shows the IRQ handler consuming a lot of CPU.
>
> update: even with acpi_pm clocksource on vanilla i can reproduce similar
> overhead using netperf.
>
> Ingo
>
Hi Ingo
I checked the clock source and in both the vanilla and rt cases and they
were both acpi_pm
Here's the oprofile for my vanilla case:
CPU: AMD64 processors, speed 2211.37 MHz (estimated)
Counted CPU_CLK_UNHALTED events (Cycles outside of halt state) with a
unit mask of 0x00 (No unit mask) count 100000
samples % image name app name
symbol name
36264 18.2763 forcedeth.ko forcedeth
nv_nic_irq_optimized
25602 12.9029 vmlinux vmlinux
spurious_interrupt
10067 5.0736 forcedeth.ko forcedeth
nv_start_xmit_optimized
8671 4.3700 vmlinux vmlinux
unregister_kprobe
8270 4.1679 vmlinux vmlinux
ctrl_dumpfamily
8042 4.0530 vmlinux vmlinux
expand_files
5064 2.5521 vmlinux vmlinux kfree
4365 2.1999 libc-2.5.so libc-2.5.so
__sendto_nocancel
4067 2.0497 vmlinux vmlinux
unix_bind
4010 2.0210 vmlinux vmlinux bad_gs
3929 1.9801 vmlinux vmlinux
__alloc_skb
3859 1.9449 vmlinux vmlinux
stack_segment
3107 1.5659 vmlinux vmlinux
__find_get_block
2816 1.4192 vmlinux vmlinux
vfs_create
2611 1.3159 vmlinux vmlinux
ide_end_drive_cmd
2604 1.3124 vmlinux vmlinux
ide_end_request
2560 1.2902 vmlinux vmlinux
find_get_page
2458 1.2388 vmlinux vmlinux
hrtimer_run_queues
2456 1.2378 vmlinux vmlinux
get_wchan
2403 1.2111 forcedeth.ko forcedeth
nv_tx_done_optimized
2231 1.1244 vmlinux vmlinux
do_sys_poll
Any thoughts?
Thanks
Dave
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-02 8:17 ` Dave Sperry
@ 2007-04-02 9:37 ` Ingo Molnar
0 siblings, 0 replies; 16+ messages in thread
From: Ingo Molnar @ 2007-04-02 9:37 UTC (permalink / raw)
To: Dave Sperry; +Cc: linux-rt-users, linux-kernel
* Dave Sperry <dave_sperry@ieee.org> wrote:
> I checked the clock source and in both the vanilla and rt cases and
> they were both acpi_pm
ok, thanks for double-checking that.
> Here's the oprofile for my vanilla case:
i tried your workload and i think i managed to optimize it some more: i
have uploaded the -rt8 kernel with these improvements included - could
you try it? Is there any measurable improvement relative to -rt5?
one more thing to improve netperf performance is to do this before
running it:
chrt -f -p 50 $$
this will put netperf on the same priority level as the net hardirq and
the net softirq (which both default to SCHED_FIFO:50), and should result
in a (much) reduced context-switch rate.
Or, if networking is not latency-critical, then you could move the net
hardirq and softirq threads to SCHED_BATCH, and run netperf under
SCHED_BATCH as well, using:
chrt -b -p 0 $$
and figuring out the active softirq hardirq thread PIDs and "chrt -b"
-ing them too.
Ingo
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-03 0:09 ` David Sperry
2007-04-03 6:43 ` Ingo Molnar
@ 2007-04-03 8:51 ` Ingo Molnar
1 sibling, 0 replies; 16+ messages in thread
From: Ingo Molnar @ 2007-04-03 8:51 UTC (permalink / raw)
To: David Sperry; +Cc: 'dave_sperry@ieee.org', linux-rt-users, linux-kernel
* David Sperry <dave_sperry@ieee.org> wrote:
> > there are a few other things i'm working on to improve this. I've
> > uploaded -rt9 which is the current state of affairs. Note that using
> > -rt9 you'll likely only see IRQ-8406 overhead in the system, because
> > i've added an optimization to do process the softirq-net-tx workload
> > in the hardirq thread if the priority of the two is the same (which
> > is the default behavior). But -rt9 is still work in progress that is
> > not fully finished yet: in some cases i'm seeing 'fluctuating
> > performance' problems on forcedeth that werent there before.
>
> I tried -rt9 and saw some odd 'fluctuating performance'. I'll try it
> again tomorrow when I am much closer to the box's power button.
could you try -rt10? I've improved hardirq/softirq threading performance
some more, and have tuned the forcedeth driver too.
Ingo
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-03 0:09 ` David Sperry
@ 2007-04-03 6:43 ` Ingo Molnar
2007-04-03 8:51 ` Ingo Molnar
1 sibling, 0 replies; 16+ messages in thread
From: Ingo Molnar @ 2007-04-03 6:43 UTC (permalink / raw)
To: David Sperry; +Cc: 'dave_sperry@ieee.org', linux-rt-users, linux-kernel
* David Sperry <dave_sperry@ieee.org> wrote:
> > > I think there is some kind of bad behavior happening in the Nvidia
> > > driver with respect to softirq-net-tx and IRQ-8406.
> >
> > yes. Part of the problem is that the forcedeth.c driver does not
> > fully support NAPI - today i've implemented those bits (see them
> > below), based on your testcase. The other part is that the Intel NIC
> > uses MSI, while foredeth uses fasteoi, correct? [you can see this in
> > /proc/interrupts]
>
> In my case forcedeth seems to be picking up MSI for eth2 & eth3
> Could this be part of my problem?
i dont think it should be a problem.
Ingo
^ permalink raw reply [flat|nested] 16+ messages in thread
* RE: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-02 19:04 ` Ingo Molnar
@ 2007-04-03 0:09 ` David Sperry
2007-04-03 6:43 ` Ingo Molnar
2007-04-03 8:51 ` Ingo Molnar
0 siblings, 2 replies; 16+ messages in thread
From: David Sperry @ 2007-04-03 0:09 UTC (permalink / raw)
To: 'Ingo Molnar', 'dave_sperry@ieee.org'
Cc: linux-rt-users, linux-kernel
> -----Original Message-----
> From: Ingo Molnar [mailto:mingo@elte.hu]
> Sent: Monday, April 02, 2007 3:05 PM
> To: dave_sperry@ieee.org
> Cc: Dave Sperry; linux-rt-users@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: Re: Poor UDP performance using 2.6.21-rc5-rt5
>
>
> * dave_sperry@ieee.org <dasperry@comcast.net> wrote:
>
> > The Intel NIC seems to behave better under RT
>
> yeah.
>
> > I think there is some kind of bad behavior happening in the Nvidia
> > driver with respect to softirq-net-tx and IRQ-8406.
>
> yes. Part of the problem is that the forcedeth.c driver does not fully
> support NAPI - today i've implemented those bits (see them below), based
> on your testcase. The other part is that the Intel NIC uses MSI, while
> foredeth uses fasteoi, correct? [you can see this in /proc/interrupts]
In my case forcedeth seems to be picking up MSI for eth2 & eth3
]$ cat /proc/interrupts
CPU0 CPU1
0: 110 0 IO-APIC-edge timer
1: 0 10 IO-APIC-edge i8042
8: 0 0 IO-APIC-edge rtc
9: 0 0 IO-APIC-fasteoi acpi
12: 0 124 IO-APIC-edge i8042
20: 0 0 IO-APIC-fasteoi libata
21: 4 7755 IO-APIC-fasteoi libata
22: 0 5570 IO-APIC-fasteoi ehci_hcd:usb2
23: 0 1 IO-APIC-fasteoi ohci_hcd:usb1, libata
8406: 7 15969 PCI-MSI-edge eth3
8407: 8 17249 PCI-MSI-edge eth2
8408: 0 131 PCI-MSI-edge eth1
8409: 0 85 PCI-MSI-edge eth0
NMI: 0 0
LOC: 201594 202389
ERR: 0
Could this be part of my problem?
The lspci for the device is:
00:08.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3)
Subsystem: Super Micro Computer Inc Unknown device 1611
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B-
Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
Latency: 0 (250ns min, 5000ns max)
Interrupt: pin A routed to IRQ 8407
Region 0: Memory at fe9ba000 (32-bit, non-prefetchable) [size=4K]
Region 1: I/O ports at a400 [size=8]
Region 2: Memory at fe9be800 (32-bit, non-prefetchable) [size=256]
Region 3: Memory at fe9be400 (32-bit, non-prefetchable) [size=16]
Capabilities: [44] Power Management version 2
Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA
PME(D0+,D1+,D2+,D3hot+,D3cold+)
Status: D0 PME-Enable+ DSel=0 DScale=0 PME-
Capabilities: [70] MSI-X: Enable- Mask- TabSize=8
Vector table: BAR=2 offset=00000000
PBA: BAR=3 offset=00000000
Capabilities: [50] Message Signalled Interrupts: 64bit+ Queue=0/3
Enable+
Address: 00000000fee0300c Data: 41b9
Capabilities: [6c] HyperTransport: MSI Mapping
00:09.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3)
Subsystem: Super Micro Computer Inc Unknown device 1611
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B-
Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
Latency: 0 (250ns min, 5000ns max)
Interrupt: pin A routed to IRQ 8406
Region 0: Memory at fe9b9000 (32-bit, non-prefetchable) [size=4K]
Region 1: I/O ports at a080 [size=8]
Region 2: Memory at fe9be000 (32-bit, non-prefetchable) [size=256]
Region 3: Memory at fe9b8c00 (32-bit, non-prefetchable) [size=16]
Capabilities: [44] Power Management version 2
Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA
PME(D0+,D1+,D2+,D3hot+,D3cold+)
Status: D0 PME-Enable+ DSel=0 DScale=0 PME-
Capabilities: [70] MSI-X: Enable- Mask- TabSize=8
Vector table: BAR=2 offset=00000000
PBA: BAR=3 offset=00000000
Capabilities: [50] Message Signalled Interrupts: 64bit+ Queue=0/3
Enable+
Address: 00000000fee0300c Data: 41c1
Capabilities: [6c] HyperTransport: MSI Mapping
>
> there are a few other things i'm working on to improve this. I've
> uploaded -rt9 which is the current state of affairs. Note that using
> -rt9 you'll likely only see IRQ-8406 overhead in the system, because
> i've added an optimization to do process the softirq-net-tx workload in
> the hardirq thread if the priority of the two is the same (which is the
> default behavior). But -rt9 is still work in progress that is not fully
> finished yet: in some cases i'm seeing 'fluctuating performance'
> problems on forcedeth that werent there before.
I tried -rt9 and saw some odd 'fluctuating performance'. I'll try it again
tomorrow when I am much closer to the box's power button.
Thanks again,
Dave
>
> Ingo
>
> --------------------->
> From: Ingo Molnar <mingo@elte.hu>
> Subject: [patch] forcedeth.c: improve NAPI handler
>
> another forcedeth.c thing: i noticed that its NAPI handler does not do
> tx-ring processing. The patch below implements this - tested on
> DESC_VER_2 hardware, with CONFIG_FORCEDETH_NAPI=y.
>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
>
> Index: linux/drivers/net/forcedeth.c
> ===================================================================
> --- linux.orig/drivers/net/forcedeth.c
> +++ linux/drivers/net/forcedeth.c
> @@ -3118,9 +3118,17 @@ static int nv_napi_poll(struct net_devic
> int retcode;
>
> if (np->desc_ver == DESC_VER_1 || np->desc_ver == DESC_VER_2) {
> + spin_lock_irqsave(&np->lock, flags);
> + nv_tx_done(dev);
> + spin_unlock_irqrestore(&np->lock, flags);
> +
> pkts = nv_rx_process(dev, limit);
> retcode = nv_alloc_rx(dev);
> } else {
> + spin_lock_irqsave(&np->lock, flags);
> + nv_tx_done_optimized(dev, np->tx_ring_size);
> + spin_unlock_irqrestore(&np->lock, flags);
> +
> pkts = nv_rx_process_optimized(dev, limit);
> retcode = nv_alloc_rx_optimized(dev);
> }
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-02 17:50 dave_sperry@ieee.org
@ 2007-04-02 19:04 ` Ingo Molnar
2007-04-03 0:09 ` David Sperry
0 siblings, 1 reply; 16+ messages in thread
From: Ingo Molnar @ 2007-04-02 19:04 UTC (permalink / raw)
To: dave_sperry@ieee.org; +Cc: Dave Sperry, linux-rt-users, linux-kernel
* dave_sperry@ieee.org <dasperry@comcast.net> wrote:
> The Intel NIC seems to behave better under RT
yeah.
> I think there is some kind of bad behavior happening in the Nvidia
> driver with respect to softirq-net-tx and IRQ-8406.
yes. Part of the problem is that the forcedeth.c driver does not fully
support NAPI - today i've implemented those bits (see them below), based
on your testcase. The other part is that the Intel NIC uses MSI, while
foredeth uses fasteoi, correct? [you can see this in /proc/interrupts]
there are a few other things i'm working on to improve this. I've
uploaded -rt9 which is the current state of affairs. Note that using
-rt9 you'll likely only see IRQ-8406 overhead in the system, because
i've added an optimization to do process the softirq-net-tx workload in
the hardirq thread if the priority of the two is the same (which is the
default behavior). But -rt9 is still work in progress that is not fully
finished yet: in some cases i'm seeing 'fluctuating performance'
problems on forcedeth that werent there before.
Ingo
--------------------->
From: Ingo Molnar <mingo@elte.hu>
Subject: [patch] forcedeth.c: improve NAPI handler
another forcedeth.c thing: i noticed that its NAPI handler does not do
tx-ring processing. The patch below implements this - tested on
DESC_VER_2 hardware, with CONFIG_FORCEDETH_NAPI=y.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Index: linux/drivers/net/forcedeth.c
===================================================================
--- linux.orig/drivers/net/forcedeth.c
+++ linux/drivers/net/forcedeth.c
@@ -3118,9 +3118,17 @@ static int nv_napi_poll(struct net_devic
int retcode;
if (np->desc_ver == DESC_VER_1 || np->desc_ver == DESC_VER_2) {
+ spin_lock_irqsave(&np->lock, flags);
+ nv_tx_done(dev);
+ spin_unlock_irqrestore(&np->lock, flags);
+
pkts = nv_rx_process(dev, limit);
retcode = nv_alloc_rx(dev);
} else {
+ spin_lock_irqsave(&np->lock, flags);
+ nv_tx_done_optimized(dev, np->tx_ring_size);
+ spin_unlock_irqrestore(&np->lock, flags);
+
pkts = nv_rx_process_optimized(dev, limit);
retcode = nv_alloc_rx_optimized(dev);
}
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
@ 2007-04-02 17:50 dave_sperry@ieee.org
2007-04-02 19:04 ` Ingo Molnar
0 siblings, 1 reply; 16+ messages in thread
From: dave_sperry@ieee.org @ 2007-04-02 17:50 UTC (permalink / raw)
To: Ingo Molnar; +Cc: Dave Sperry, linux-rt-users, linux-kernel
I have a new data point to add to the confusion.
The box I'm testing has 2 nics in it. The one I have been testing so far is:
00:08.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3)
The other NIC is an Intel 1gig fiber
09:00.0 Ethernet controller: Intel Corporation 82571EB Gigabit Ethernet Controller (rev 06)
The Intel controller did not work 2.6.20 but under 2.6.21-rc5-rt8 it does.
Running the same netperf tests with the Intel NIC produces very different results for the RT case:
setup Thruput CPU%
Nvidia
2.6.21-rc5 vanilla 935 29%
netperf @51
hardirq @50
softirq @50
Intel
2.6.21-rc5 vanilla 933 30%
netperf @51
hardirq @50
softirq @50
##################################################
Nvidia
2.6.21-rc5-rt8 938 65%
netperf @51
hardirq @50
softirq @50
Intel
2.6.21-rc5-rt8 938 34%
netperf @51
hardirq @50
softirq @50
The Intel NIC seems to behave better under RT
top for each NIC under test yields some interesting results:
Nvidia 2.6.21-rc5-rt8:
top - 11:03:46 up 1:23, 2 users, load average: 1.75, 1.31, 0.70
Tasks: 167 total, 2 running, 165 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.8%us, 29.7%sy, 0.0%ni, 34.8%id, 0.0%wa, 22.1%hi, 10.6%si, 0.0%st
Mem: 2035436k total, 618276k used, 1417160k free, 31744k buffers
Swap: 3068372k total, 0k used, 3068372k free, 386060k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
4139 root -52 0 6440 636 480 S 60 0.0 0:19.14 netperf
2706 root -51 -5 0 0 0 R 44 0.0 2:00.70 IRQ-8406
19 root -51 0 0 0 0 S 21 0.0 0:38.50 softirq-net-tx/
4012 eadi 16 0 229m 6852 5584 S 1 0.3 0:05.39 multiload-apple
6 root -51 0 0 0 0 S 1 0.0 0:00.95 softirq-net-tx/
3014 dbus 15 0 21352 896 548 S 1 0.0 0:00.04 dbus-daemon
1 root 15 0 10308 668 552 S 0 0.0 0:00.74 init
2 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0
3 root RT 0 0 0 0 S 0 0.0 0:00.00 posix_cpu_timer
4 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-high/0
5 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-timer/0
7 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-net-rx/
8 root -51 0 0 0 0 S 0 0.0 0:00.01 softirq-block/0
########################
Intel 2.6.21-rc5-rt8
top - 11:10:27 up 3 min, 2 users, load average: 0.00, 0.00, 0.00
Tasks: 167 total, 1 running, 166 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.5%us, 21.6%sy, 0.0%ni, 65.9%id, 0.0%wa, 3.0%hi, 9.0%si, 0.0%st
Mem: 2035436k total, 618012k used, 1417424k free, 29972k buffers
Swap: 3068372k total, 0k used, 3068372k free, 386084k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3955 root -52 0 6436 636 480 S 43 0.0 0:19.74 netperf
20 root -51 0 0 0 0 S 11 0.0 0:04.86 softirq-net-rx/
7 root -51 0 0 0 0 S 7 0.0 0:03.28 softirq-net-rx/
2370 root -51 -5 0 0 0 S 6 0.0 0:02.62 IRQ-8408
3858 eadi 16 0 229m 6848 5584 S 1 0.3 0:01.45 multiload-apple
3954 eadi 15 0 12712 1096 788 R 0 0.1 0:00.19 top
1 root 15 0 10304 664 552 S 0 0.0 0:00.75 init
2 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0
3 root RT 0 0 0 0 S 0 0.0 0:00.00 posix_cpu_timer
4 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-high/0
5 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-timer/0
6 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-net-tx/
8 root -51 0 0 0 0 S 0 0.0 0:00.01 softirq-block/0
9 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-tasklet
10 root -51 0 0 0 0 S 0 0.0 0:00.00 softirq-sched/0
############################
I think there is some kind of bad behavior happening in the Nvidia driver
with respect to softirq-net-tx and IRQ-8406.
Any thoughts? If you want I can post the oprofile from both test cases.
-Dave
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
@ 2007-04-02 17:17 dave_sperry@ieee.org
0 siblings, 0 replies; 16+ messages in thread
From: dave_sperry@ieee.org @ 2007-04-02 17:17 UTC (permalink / raw)
To: Ingo Molnar; +Cc: Dave Sperry, linux-rt-users, linux-kernel
-------------- Original message ----------------------
From: Ingo Molnar <mingo@elte.hu>
>
> * dave_sperry@ieee.org <dasperry@comcast.net> wrote:
>
> > Thanks for all the input Ingo, Here's a list of all the permutations
> > I've tried:
>
> one thing i noticed is that cyclesoak interferes with the netperf
> workload. This is quite surprising. 'top' and 'vmstat' output is
> reliable on -rt, and the overhead goes down if i stop cyclesoak.
>
> Ingo
I see the same effect
setup Thruput CPU%
cyclesoak on
2.6.21-rc5-rt8 937 74%
netperf @51
hardirq @50
softirq @50
cyclesoak off
2.6.21-rc5-rt8 938 65%
netperf @51
hardirq @50
softirq @50
Dave
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
2007-04-02 14:09 dave_sperry@ieee.org
@ 2007-04-02 14:23 ` Ingo Molnar
0 siblings, 0 replies; 16+ messages in thread
From: Ingo Molnar @ 2007-04-02 14:23 UTC (permalink / raw)
To: dave_sperry@ieee.org; +Cc: Dave Sperry, linux-rt-users, linux-kernel
* dave_sperry@ieee.org <dasperry@comcast.net> wrote:
> Thanks for all the input Ingo, Here's a list of all the permutations
> I've tried:
one thing i noticed is that cyclesoak interferes with the netperf
workload. This is quite surprising. 'top' and 'vmstat' output is
reliable on -rt, and the overhead goes down if i stop cyclesoak.
Ingo
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Poor UDP performance using 2.6.21-rc5-rt5
@ 2007-04-02 14:09 dave_sperry@ieee.org
2007-04-02 14:23 ` Ingo Molnar
0 siblings, 1 reply; 16+ messages in thread
From: dave_sperry@ieee.org @ 2007-04-02 14:09 UTC (permalink / raw)
To: Ingo Molnar, Dave Sperry; +Cc: linux-rt-users, linux-kernel
Thanks for all the input Ingo, Here's a list of all the permutations I've tried:
setup Thruput CPU% from cyclesoak
2.6.21-rc5 vanilla 935 29%
2.6.21-rc5-rt5 711 50% //basically all of 1 cpu
2.6.21-rc5-rt8 733 52%
2.6.21-rc5-rt8 824 64%
netperf @50
hardirq @50
softirq @50
2.6.21-rc5-rt8 937 74%
netperf @51
hardirq @50
softirq @50
2.6.21-rc5-rt8 106 8%
netperf @51
hardirq @49
softirq @50
2.6.21-rc5-rt8 233 14%
netperf @51
hardirq @49
softirq @48
2.6.21-rc5-rt8 67 5%
netperf @batch
hardirq @batch
softirq @batch
2.6.21-rc5-rt8 331 OFF
netperf @batch
hardirq @batch
softirq @batch
cyclesoak off
Any thoughts?
-Dave
-------------- Original message ----------------------
From: Ingo Molnar <mingo@elte.hu>
>
> * Dave Sperry <dave_sperry@ieee.org> wrote:
>
> > I checked the clock source and in both the vanilla and rt cases and
> > they were both acpi_pm
>
> ok, thanks for double-checking that.
>
> > Here's the oprofile for my vanilla case:
>
> i tried your workload and i think i managed to optimize it some more: i
> have uploaded the -rt8 kernel with these improvements included - could
> you try it? Is there any measurable improvement relative to -rt5?
>
> one more thing to improve netperf performance is to do this before
> running it:
>
> chrt -f -p 50 $$
>
> this will put netperf on the same priority level as the net hardirq and
> the net softirq (which both default to SCHED_FIFO:50), and should result
> in a (much) reduced context-switch rate.
>
> Or, if networking is not latency-critical, then you could move the net
> hardirq and softirq threads to SCHED_BATCH, and run netperf under
> SCHED_BATCH as well, using:
>
> chrt -b -p 0 $$
>
> and figuring out the active softirq hardirq thread PIDs and "chrt -b"
> -ing them too.
>
> Ingo
^ permalink raw reply [flat|nested] 16+ messages in thread
end of thread, other threads:[~2007-04-03 8:51 UTC | newest]
Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2007-04-01 19:15 Poor UDP performance using 2.6.21-rc5-rt5 Dave Sperry
2007-04-01 20:07 ` Nivedita Singhvi
2007-04-01 22:00 ` Dave Sperry
2007-04-02 5:55 ` Ingo Molnar
2007-04-02 6:30 ` Ingo Molnar
2007-04-02 7:21 ` Ingo Molnar
2007-04-02 8:17 ` Dave Sperry
2007-04-02 9:37 ` Ingo Molnar
2007-04-02 14:09 dave_sperry@ieee.org
2007-04-02 14:23 ` Ingo Molnar
2007-04-02 17:17 dave_sperry@ieee.org
2007-04-02 17:50 dave_sperry@ieee.org
2007-04-02 19:04 ` Ingo Molnar
2007-04-03 0:09 ` David Sperry
2007-04-03 6:43 ` Ingo Molnar
2007-04-03 8:51 ` Ingo Molnar
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