On 09/03/2013 10:44 AM, Vineet Gupta wrote:
b) Could you check that it is not just a performance regression?
Does ./msgctl08 1000 16 hang, too?
Nope that doesn't hang. The minimal configuration that hangs reliably is msgctl
50000 2
With this config there are 3 processes.
...
555 554 root S 1208 0.4 0 0.0 ./msgctl08 50000 2
554 551 root S 1208 0.4 0 0.0 ./msgctl08 50000 2
551 496 root S 1208 0.4 0 0.0 ./msgctl08 50000 2
...
[ARCLinux]$ cat /proc/551/stack
[<80aec3c6>] do_wait+0xa02/0xc94
[<80aecad2>] SyS_wait4+0x52/0xa4
[<80ae24fc>] ret_from_system_call+0x0/0x4
[ARCLinux]$ cat /proc/555/stack
[<80c2950e>] SyS_msgrcv+0x252/0x420
[<80ae24fc>] ret_from_system_call+0x0/0x4
[ARCLinux]$ cat /proc/554/stack
[<80c28c82>] do_msgsnd+0x116/0x35c
[<80ae24fc>] ret_from_system_call+0x0/0x4
Is this a case of lost wakeup or some such. I'm running with some more diagnostics
and will report soon ...
What is the output of ipcs -q? Is the queue full or empty when it hangs?
I.e. do we forget to wake up a receiver or forget to wake up a sender?
--
Manfred
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