Re: [PATCH] eal: fix threads block on barrier

[Shreyansh Jain <shreyansh.jain@nxp.com>]

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Jianfeng Tan
> Sent: Friday, April 27, 2018 10:12 PM
> To: dev@dpdk.org
> Cc: thomas@monjalon.net; Jianfeng Tan <jianfeng.tan@intel.com>; Olivier
> Matz <olivier.matz@6wind.com>; Anatoly Burakov
> <anatoly.burakov@intel.com>
> Subject: [dpdk-dev] [PATCH] eal: fix threads block on barrier
> 
> Below commit introduced pthread barrier for synchronization.
> But two IPC threads block on the barrier, and never wake up.
> 
>   (gdb) bt
>   #0  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  rte_thread_init (arg=0x7fffffffcfe0)
>       at ../dpdk/lib/librte_eal/common/eal_common_thread.c:160
>   #4  start_thread (arg=0x7ffff6ecf700) at pthread_create.c:333
>   #5  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109
> 
> Through analysis, we find the barrier defined on the stack could be the
> root cause. This patch will change to use heap memory as the barrier.
> 
> Fixes: d651ee4919cd ("eal: set affinity for control threads")
> 
> Cc: Olivier Matz <olivier.matz@6wind.com>
> Cc: Anatoly Burakov <anatoly.burakov@intel.com>
> 
> Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>

Though I have seen Stephen's comment on this (possibly a library bug), this at least fixes an issue which was dogging dpaa and dpaa2 - generating bus errors and futex errors with variation in core masks provided to applications.

Thanks a lot for this.

Acked-by: Shreyansh Jain <shreyansh.jain@nxp.com>