Hi Jiangfeng,

On 05/02/2018 10:19 AM, Tan, Jianfeng wrote:


On 5/1/2018 2:46 AM, Olivier Matz wrote:
Hi Maxime,

Le 30 avril 2018 17:45:52 GMT+02:00, Maxime Coquelin <maxime.coque...@redhat.com> a écrit :
Hi Olivier,

On 04/24/2018 04:46 PM, Olivier Matz wrote:
Some parts of dpdk use their own management threads. Most of the
time,
the affinity of the thread is not properly set: it should not be
scheduled
on the dataplane cores, because interrupting them can cause packet
losses.
This patchset introduces a new wrapper for thread creation that does
the job automatically, avoiding code duplication.

v3:
* new patch: use this API in examples when relevant.
* replace pthread_kill by pthread_cancel. Note that pthread_join()
    is still needed.
* rebase: vfio and pdump do not have control pthreads anymore, and
eal
    has 2 new pthreads
* remove all calls to snprintf/strlcpy that truncate the thread name:
    all strings lengths are already < 16.

v2:
* set affinity to master core if no core is off, as suggested by
    Anatoly

Olivier Matz (5):
    eal: use sizeof to avoid a double use of a define
    eal: new function to create control threads
    eal: set name when creating a control thread
    eal: set affinity for control threads
    examples: use new API to create control threads

   drivers/net/kni/Makefile                     |  1 +
   drivers/net/kni/rte_eth_kni.c                |  3 +-
   examples/tep_termination/main.c              | 16 +++----
   examples/vhost/main.c                        | 19 +++-----
   lib/librte_eal/bsdapp/eal/eal.c              |  4 +-
   lib/librte_eal/bsdapp/eal/eal_thread.c       |  2 +-
   lib/librte_eal/common/eal_common_proc.c      | 15 ++----
   lib/librte_eal/common/eal_common_thread.c    | 72
++++++++++++++++++++++++++++
   lib/librte_eal/common/include/rte_lcore.h    | 26 ++++++++++
   lib/librte_eal/linuxapp/eal/eal.c            |  4 +-
   lib/librte_eal/linuxapp/eal/eal_interrupts.c | 17 ++-----
   lib/librte_eal/linuxapp/eal/eal_thread.c     |  2 +-
   lib/librte_eal/linuxapp/eal/eal_timer.c      | 12 +----
   lib/librte_eal/rte_eal_version.map           |  1 +
   lib/librte_vhost/socket.c                    | 25 ++--------
   15 files changed, 135 insertions(+), 84 deletions(-)

I face a deadlock issue with your series, that Jianfeng patch does not
resolve ("eal: fix threads block on barrier"). Reverting the series and
Jianfeng patch makes the issue to disappear.

I face the problem in a VM (not seen on the host):
# ./install/bin/testpmd -l 0,1,2 --socket-mem 1024 -n 4 --proc-type
auto
--file-prefix pg -- --portmask=3 --forward-mode=macswap
--port-topology=chained --disable-rss -i --rxq=1 --txq=1 --rxd=256
--txd=256 --nb-cores=2 --auto-start
EAL: Detected 3 lcore(s)
EAL: Detected 1 NUMA nodes
EAL: Auto-detected process type: PRIMARY
EAL: Multi-process socket /var/run/.pg_unix


Then it is stuck. Attaching with GDB, I get below backtrace
information:

(gdb) info threads
   Id   Target Id         Frame
   3    Thread 0x7f63e1f9f700 (LWP 8808) "rte_mp_handle"
0x00007f63e2591bfd in recvmsg () at
../sysdeps/unix/syscall-template.S:81
   2    Thread 0x7f63e179e700 (LWP 8809) "rte_mp_async"
pthread_barrier_wait () at
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S:71
* 1    Thread 0x7f63e32cec00 (LWP 8807) "testpmd" pthread_barrier_wait
() at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S:71
(gdb) bt full
#0  pthread_barrier_wait () at
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S:71
No locals.
#1  0x0000000000520c54 in rte_ctrl_thread_create
(thread=thread@entry=0x7ffe5c895020, name=name@entry=0x869d86
"rte_mp_async", attr=attr@entry=0x0,
start_routine=start_routine@entry=0x521030 <async_reply_handle>,
arg=arg@entry=0x0)
     at /root/src/dpdk/lib/librte_eal/common/eal_common_thread.c:207
         params = 0x17b1e40
         lcore_id = <optimized out>
         cpuset = {__bits = {1, 0 <repeats 15 times>}}
         cpu_found = <optimized out>
         ret = 0
#2  0x00000000005220b6 in rte_mp_channel_init () at
/root/src/dpdk/lib/librte_eal/common/eal_common_proc.c:674
        path = "/var/run\000.pg_unix_*", '\000' <repeats 1301 times>...
         dir_fd = 4
         mp_handle_tid = 140066969745152
         async_reply_handle_tid = 140066961352448
#3  0x000000000050c227 in rte_eal_init (argc=argc@entry=23,
argv=argv@entry=0x7ffe5c896378) at
/root/src/dpdk/lib/librte_eal/linuxapp/eal/eal.c:775
         i = <optimized out>
         fctret = 11
         ret = <optimized out>
         thread_id = 140066989861888
         run_once = {cnt = 1}
         logid = 0x17b1e00 "testpmd"
         cpuset = "T}\211\\\376\177", '\000' <repeats 117 times>,
"\020", '\000' <repeats 116 times>...
      thread_name = "X}\211\\\376\177\000\000\226\301\036\342c\177\000"
         __func__ = "rte_eal_init"
#4  0x0000000000473214 in main (argc=23, argv=0x7ffe5c896378) at
/root/src/dpdk/app/test-pmd/testpmd.c:2597
         diag = <optimized out>
         port_id = <optimized out>
         ret = <optimized out>
         __func__ = "main"
(gdb) thread 2
[Switching to thread 2 (Thread 0x7f63e179e700 (LWP 8809))]
#0  pthread_barrier_wait () at
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S:71
71        cmpl    %edx, (%rdi)
(gdb) bt full
#0  pthread_barrier_wait () at
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S:71
No locals.
#1  0x0000000000520777 in rte_thread_init (arg=<optimized out>) at
/root/src/dpdk/lib/librte_eal/common/eal_common_thread.c:156
         params = <optimized out>
         start_routine = 0x521030 <async_reply_handle>
         routine_arg = 0x0
#2  0x00007f63e258add5 in start_thread (arg=0x7f63e179e700) at
pthread_create.c:308
         __res = <optimized out>
         pd = 0x7f63e179e700
         now = <optimized out>
         unwind_buf = {cancel_jmp_buf = {{jmp_buf = {140066961352448,
1212869169857371576, 0, 8392704, 0, 140066961352448,
-1291626103561052744, -1291619793368703560}, mask_was_saved = 0}}, priv

= {pad = {0x0, 0x0, 0x0, 0x0}, data = {
               prev = 0x0, cleanup = 0x0, canceltype = 0}}}
         not_first_call = <optimized out>
         pagesize_m1 = <optimized out>
         sp = <optimized out>
         freesize = <optimized out>
#3  0x00007f63e22b4b3d in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:113
No locals.
(gdb) thread 3
[Switching to thread 3 (Thread 0x7f63e1f9f700 (LWP 8808))]
#0  0x00007f63e2591bfd in recvmsg () at
../sysdeps/unix/syscall-template.S:81
81    T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
(gdb) bt full
#0  0x00007f63e2591bfd in recvmsg () at
../sysdeps/unix/syscall-template.S:81
No locals.
#1  0x000000000052194e in read_msg (s=0x7f63e1f9d3b0, m=0x7f63e1f9d5a0)

at /root/src/dpdk/lib/librte_eal/common/eal_common_proc.c:258
         msglen = <optimized out>
         control =
"\000\000\000\000\000\000\000\000\336~\f\343c\177\000\000\005", '\000'
<repeats 23 times>, "\360\371\033\342c\177\000"
         cmsg = <optimized out>
         iov = {iov_base = 0x7f63e1f9d5a0, iov_len = 332}
       msgh = {msg_name = 0x7f63e1f9d3b0, msg_namelen = 110, msg_iov =
0x7f63e1f9d370, msg_iovlen = 1, msg_control = 0x7f63e1f9d380,
msg_controllen = 48, msg_flags = 0}
#2  mp_handle (arg=<optimized out>) at
/root/src/dpdk/lib/librte_eal/common/eal_common_proc.c:346
         msg = {type = 0, msg = {name = '\000' <repeats 63 times>,
len_param = 0, num_fds = 0, param = '\000' <repeats 20 times>, "\002",
'\000' <repeats 234 times>, fds = {0, 0, 0, 0, 0, 0, 0, 0}}}
         sa = {sun_family = 55104,
           sun_path =
"\371\341c\177\000\000\352\372\f\343c\177\000\000\000\000\000\000\000\000\000\000\377\377\377\377\377\377\377\377\000\367\371\341c\177\000\000\030\000\000\000\000\000\000\000p\327\371\341c\177\000\000\000\367\371\341c\177\000\000\000\367\371\341c\177",

'\000' <repeats 34 times>, "\200\037\000\000\377\377"}
#3  0x00007f63e258add5 in start_thread (arg=0x7f63e1f9f700) at
pthread_create.c:308
         __res = <optimized out>
         pd = 0x7f63e1f9f700
         now = <optimized out>
         unwind_buf = {cancel_jmp_buf = {{jmp_buf = {140066969745152,
1212869169857371576, 0, 8392704, 0, 140066969745152,
-1291625004586295880, -1291619793368703560}, mask_was_saved = 0}}, priv

= {pad = {0x0, 0x0, 0x0, 0x0}, data = {
               prev = 0x0, cleanup = 0x0, canceltype = 0}}}
         not_first_call = <optimized out>
         pagesize_m1 = <optimized out>
         sp = <optimized out>
         freesize = <optimized out>
#4  0x00007f63e22b4b3d in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:113
No locals.

I don't have more info for now.


Thanks for the feedback on this issue. I don't see obvious reason for this deadlock yet.

I'll investigate it asap (not tomorrow, but wednesday). In the worst case, we can revert the series if I cannot find the root cause rapidly.

I might think that the suggestion from Stephen of destroying the barrier can help this issue. I'll try to reproduce it and test it before sending a patch to fix it.

In case you don't reproduce, feel free to send me the patch to test it.

Thanks,
Maxime

Thanks,
Jianfeng


Olivier


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