[dpdk-dev] [PATCH v3 3/5] eal: set name when creating a control thread

Tan, Jianfeng jianfeng.tan at intel.com
Fri Apr 27 18:17:00 CEST 2018



On 4/27/2018 11:46 PM, Tan, Jianfeng wrote:
> Hi Olivier,
>
> After this patch, I find the two IPC threads block at 
> pthread_barrier_wait(), and never wake up. Please refer below for more 
> information. The system is Ubuntu 16.04.
>
> On 4/24/2018 10:46 PM, Olivier Matz wrote:
>> To avoid code duplication, add a parameter to rte_ctrl_thread_create()
>> to specify the name of the thread.
>>
>> This requires to add a wrapper for the thread start routine in
>> rte_thread_init(), which will first wait that the thread is configured.
>>
>> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
>> ---
>>   drivers/net/kni/rte_eth_kni.c                |  3 +-
>>   lib/librte_eal/common/eal_common_proc.c      | 15 +++-----
>>   lib/librte_eal/common/eal_common_thread.c    | 52 
>> +++++++++++++++++++++++++---
>>   lib/librte_eal/common/include/rte_lcore.h    |  7 ++--
>>   lib/librte_eal/linuxapp/eal/eal_interrupts.c | 13 ++-----
>>   lib/librte_eal/linuxapp/eal/eal_timer.c      | 12 +------
>>   lib/librte_vhost/socket.c                    | 25 +++----------
>>   7 files changed, 66 insertions(+), 61 deletions(-)
> [...]
>> diff --git a/lib/librte_eal/common/eal_common_thread.c 
>> b/lib/librte_eal/common/eal_common_thread.c
>> index efbccddbc..94d2a6e42 100644
>> --- a/lib/librte_eal/common/eal_common_thread.c
>> +++ b/lib/librte_eal/common/eal_common_thread.c
>> @@ -7,6 +7,7 @@
>>   #include <stdint.h>
>>   #include <unistd.h>
>>   #include <pthread.h>
>> +#include <signal.h>
>>   #include <sched.h>
>>   #include <assert.h>
>>   #include <string.h>
>> @@ -141,10 +142,53 @@ eal_thread_dump_affinity(char *str, unsigned size)
>>       return ret;
>>   }
>>   +
>> +struct rte_thread_ctrl_params {
>> +    void *(*start_routine)(void *);
>> +    void *arg;
>> +    pthread_barrier_t configured;
>> +};
>> +
>> +static void *rte_thread_init(void *arg)
>> +{
>> +    struct rte_thread_ctrl_params *params = arg;
>> +    void *(*start_routine)(void *) = params->start_routine;
>> +    void *routine_arg = params->arg;
>> +
>> +    pthread_barrier_wait(&params->configured);
>
> This thread never wakes up. The call trace as below:
>
> #0  0x00007ffff72a8154 in futex_wait (private=0, expected=0, 
> futex_word=0x7fffffffcff4)
>     at ../sysdeps/unix/sysv/linux/futex-internal.h:61
> #1  futex_wait_simple (private=0, expected=0, 
> futex_word=0x7fffffffcff4) at ../sysdeps/nptl/futex-internal.h:135
> #2  __pthread_barrier_wait (barrier=0x7fffffffcff0) at 
> pthread_barrier_wait.c:184
> #3  0x000000000055216a in rte_thread_init (arg=0x7fffffffcfe0) at 
> /home/tan/git/dpdk/lib/librte_eal/common/eal_common_thread.c:160
> #4  0x00007ffff72a16ba in start_thread (arg=0x7ffff6ecf700) at 
> pthread_create.c:333
> #5  0x00007ffff6fd741d in clone () at 
> ../sysdeps/unix/sysv/linux/x86_64/clone.S:109
>
>> +
>> +    return start_routine(routine_arg);
>> +}
>> +
>>   __rte_experimental int
>> -rte_ctrl_thread_create(pthread_t *thread,
>> -            const pthread_attr_t *attr,
>> -            void *(*start_routine)(void *), void *arg)
>> +rte_ctrl_thread_create(pthread_t *thread, const char *name,
>> +        const pthread_attr_t *attr,
>> +        void *(*start_routine)(void *), void *arg)
>>   {
>> -    return pthread_create(thread, attr, start_routine, arg);
>> +    struct rte_thread_ctrl_params params = {
>> +        .start_routine = start_routine,
>> +        .arg = arg,
>> +    };

Update:

I doubt it's due to that we defined this variable, params, on the stack; 
and the value seems be overwritten by following code. Will send a patch 
to fix it.

Thanks,
Jianfeng


>> +    int ret;
>> +
>> +    pthread_barrier_init(&params.configured, NULL, 2);
>> +
>> +    ret = pthread_create(thread, attr, rte_thread_init, (void 
>> *)&params);
>> +    if (ret != 0)
>> +        return ret;
>> +
>> +    if (name != NULL) {
>> +        ret = rte_thread_setname(*thread, name);
>> +        if (ret < 0)
>> +            goto fail;
>> +    }
>> +
>> +    pthread_barrier_wait(&params.configured);
>
> Here, the thread wakes up normally, and continues.
>
> Any idea on what's going on?
>
> Thanks,
> Jianfeng
>
>> +
>> +    return 0;
>> +
>> +fail:
>> +    pthread_cancel(*thread);
>> +    pthread_join(*thread, NULL);
>> +    return ret;
>>   }
>



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