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Opened 8 years ago

Closed 8 years ago

Last modified 2 years ago

#7356 closed defect (wontfix)

sirq is consummating almost 50% of cpu

Reported by: crow Owned by: developers
Priority: normal Milestone: Backfire 10.03.1
Component: packages Version: Trunk
Keywords: Cc:

Description

This is only happening when I am downloading something from internet, which will also rezult a slow download speed, not full speed download which I have when connected PC<->isp Modem directly. The diff ist 1MB/s vs 3MB/s .

Mem: 16848K used, 12736K free, 0K shrd, 1660K buff, 5868K cached
CPU:   0% usr   0% sys   0% nic  50% idle   0% io   1% irq  46% sirq
Load average: 0.00 0.00 0.00 1/29 3113
  PID  PPID USER     STAT   VSZ %MEM %CPU COMMAND
 3113  3104 root     R     1360   5%   1% top
 1120     1 nobody   S      920   3%   1% /usr/sbin/dnsmasq -K -D -y -Z -b -E -
  844     1 root     S     1412   5%   0% hostapd -P /var/run/wifi-phy0.pid -B
  340     1 root     S     1368   5%   0% syslogd -C16
 1205     1 root     S     1368   5%   0% udhcpc -t 0 -i eth0.1 -b -p /var/run/
    1     0 root     S     1364   5%   0% init
 3104  3103 root     S     1364   5%   0% -ash
  318     1 root     S     1364   5%   0% init
  342     1 root     S     1352   5%   0% klogd
 1128     1 root     S     1348   5%   0% watchdog -t 5 /dev/watchdog
 3103  1098 root     S     1200   4%   0% /usr/sbin/dropbear -p 22 -P /var/run/
 1098     1 root     S     1144   4%   0% /usr/sbin/dropbear -p 22 -P /var/run/
  356     1 root     S      776   3%   0% /sbin/hotplug2 --override --persisten
    4     2 root     SW       0   0%   0% [events/0]
    3     2 root     SW       0   0%   0% [ksoftirqd/0]
   83     2 root     SW       0   0%   0% [mtdblockd]
    5     2 root     SW       0   0%   0% [khelper]
   25     2 root     SW       0   0%   0% [bdi-default]
   23     2 root     SW       0   0%   0% [sync_supers]
  268     2 root     SWN      0   0%   0% [jffs2_gcd_mtd3]

Attachments (0)

Change History (9)

comment:1 Changed 8 years ago by crow

I am using brcm47xx target on ASUS WL-500gP v1 device.
When downloading:

CPU:   0% usr   0% sys   0% nic  50% idle   0% io   1% irq  46% sirq

Idle state:

CPU:   0% usr   0% sys   0% nic  93% idle   0% io   0% irq   5% sirq

comment:2 Changed 8 years ago by anonymous

I installed Openwrt Blackfire r21533, from http://downloads.openwrt.org/snapshots/trunk/brcm47xx/. I have Asus WL 500gP v2. The same thing happens, when I download something from internet I reach a speed of maximum 3.5 MB/,. and sirq at top shows 90%. Also, I cannot connect to luci, or ssh, i can run commands only trough console.

comment:3 Changed 8 years ago by melinte_ionut@…

This is the mail for the previous comment.

comment:4 Changed 8 years ago by florian

  • Resolution set to wontfix
  • Status changed from new to closed

This is expected, all the network routing is done in software, so your router is extremly busy servicing Ethernet interfaces interrupts. There is not much we can do about it.

comment:5 Changed 2 years ago by Brain2000

Six years later... it seems like a number of the brcm47xx images still have this issue. The CPU usage on my Asus RT-N16 is 100% at 12Mbits of throughput.

Last edited 2 years ago by Brain2000 (previous) (diff)

comment:6 Changed 2 years ago by Brain2000

I did some research. I am using the brcmsmac driver.

According to this page (https://wireless.wiki.kernel.org/en/users/drivers/brcm80211) the brcmsmac driver does not yet support hardware encryption.

But according to this page, the brcmsmac driver does support HW encryption as of 2013 (https://wiki.openwrt.org/doc/hardware/soc/soc.broadcom.bcm47xx)

Perhaps there is a bug where the high CPU usage is occurring because it is falling back to software encryption?

Last edited 2 years ago by Brain2000 (previous) (diff)

comment:8 Changed 2 years ago by Brain2000

A bit more research reveals that the b43 driver supports HW encryption when CCMP is used, as the CPU is only hitting about 10% max. However, the bcrmsmac driver hits 100% whether the encryption is set for any combination of WPA/WPA2/CCMP/TKIP Enterprise.

(It may be worth noting that the b43 driver has high CPU usage if TKIP is used instead of CCMP, but that may be irrelavent.)

Last edited 2 years ago by Brain2000 (previous) (diff)

comment:9 Changed 2 years ago by Brain2000

Oops, I just realized that the wiki page says:

"It is still missing some functionality,

as of 2013: ...HW Based Encryption..."

I read it as if this was available as of 2013. It's written awkward.

Any OpenWRT wiki that suggests you install brcmsmac for Broadcom 802.11n functionality is a bit misleading, as you won't have hardware encryption, limiting speeds less than 20Mbits.

comment:10 Changed 2 years ago by anonymous

Problem not in encryption. Problem in network routing.
Somebody knows, there is in Asus RT-N16 original firmware hardware acceleration of routing?

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