From: Krzysztof Witkowski <Krzysztof.Witkowski@mobile.put.edu.pl>
To: Wolfgang Grandegger <wg@grandegger.com>
Cc: linux-can@vger.kernel.org
Subject: Re: CPU load inhibits CAN interrupts
Date: Wed, 11 Apr 2012 11:40:31 +0200 [thread overview]
Message-ID: <4F85518F.9020305@mobile.put.edu.pl> (raw)
In-Reply-To: <4F847253.5080507@grandegger.com>
W dniu 4/10/2012 7:48 PM, Wolfgang Grandegger pisze:
>> However, if I generate artificial CPU load with stress command:
>>
>> chrt --idle 0 stress -c 2
>
> What does "-c 2" do? My "chrt" command does not have that option.
It is an option for stress command:
-c, --cpu N
spawn N workers spinning on sqrt()
>> Why CPU load inhibits hardware interrupts and what can be done about it?
>
> Hm, what does "ip -d -s can0" report while you are producing CPU load
> with the stress command above.
# ip -s -d link show can0
4: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN
mode DEFAULT qlen 10
link/can
can state ERROR-PASSIVE (berr-counter tx 0 rx 128) restart-ms 100
bitrate 1000000 sample-point 0.750
tq 125 prop-seg 2 phase-seg1 3 phase-seg2 2 sjw 2
sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1
clock 8000000
re-started bus-errors arbit-lost error-warn error-pass bus-off
0 0 0 1 1 0
RX: bytes packets errors dropped overrun mcast
728 91 0 0 0 0
TX: bytes packets errors dropped carrier collsns
0 0 0 0 0 0
It can occasionally deliver packets, but the rate is no more than ~2
packets/second.
next prev parent reply other threads:[~2012-04-11 11:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-10 14:40 CPU load inhibits CAN interrupts Krzysztof Witkowski
2012-04-10 17:48 ` Wolfgang Grandegger
2012-04-11 9:40 ` Krzysztof Witkowski [this message]
2012-04-11 13:23 ` Wolfgang Grandegger
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