Hi,
I used valgrind again for a very long time, and it told me nothing
strange is happening on my code.
After it, I changed my code this way
unsigned lcore_id_start = rte_lcore_id();
RTE_LCORE_FOREACH(lcore_id)
{
if (lcore_id_start != lcore_id) // <--------- before this
change, every lcore could use it own mempool and enqueue to its own ring
{
new_work = NULL;
result =
rte_mempool_get(cea_main_lcore_conf[lcore_id].de_conf.cmd_pool, (VOID_P
*) &new_work); // mempools are created one for each logical core
if (result == 0)
{
if (((uint64_t)(new_work)) < 0x7f0000000000)
printf("Result %d, lcore di partenza %u, lcore
di ricezione %u, pointer %p\n", result, rte_lcore_id(), lcore_id,
new_work); // debug print, on my server it should never happen but
with multi-thread happens always on the last logical core!!!!
new_work->command = command; // usage of the memory
gotten from the mempool... <<<<<- here is where the application crashes!!!!
result =
rte_ring_enqueue(cea_main_lcore_conf[lcore_id].de_conf.cmd_ring,
(VOID_P) new_work); // enqueues the gotten buffer on the rings of all
lcores
// check on result value ...
}
else
{
// do something if result != 0 ...
}
}
else
{
// don't use mempool but call a function instead ....
}
}
and now it all goes well.
It is possibile that sending to itself could generate this issue?
Regards,
Matteo
Il 21/08/2018 16:46, Matteo Lanzuisi ha scritto:
Il 21/08/2018 14:51, Wiles, Keith ha scritto:
On Aug 21, 2018, at 7:44 AM, Matteo Lanzuisi <m.lanzu...@resi.it>
wrote:
Il 21/08/2018 14:17, Wiles, Keith ha scritto:
On Aug 21, 2018, at 7:01 AM, Matteo Lanzuisi <m.lanzu...@resi.it>
wrote:
Hi
Il 20/08/2018 18:03, Wiles, Keith ha scritto:
On Aug 20, 2018, at 9:47 AM, Matteo Lanzuisi <m.lanzu...@resi.it>
wrote:
Hello Olivier,
Il 13/08/2018 23:54, Olivier Matz ha scritto:
Hello Matteo,
On Mon, Aug 13, 2018 at 03:20:44PM +0200, Matteo Lanzuisi wrote:
Any suggestion? any idea about this behaviour?
Il 08/08/2018 11:56, Matteo Lanzuisi ha scritto:
Hi all,
recently I began using "dpdk-17.11-11.el7.x86_64" rpm (RedHat
rpm) on
RedHat 7.5 kernel 3.10.0-862.6.3.el7.x86_64 as a porting of an
application from RH6 to RH7. On RH6 I used dpdk-2.2.0.
This application is made up by one or more threads (each one
on a
different logical core) reading packets from i40e interfaces.
Each thread can call the following code lines when receiving
a specific
packet:
RTE_LCORE_FOREACH(lcore_id)
{
result =
rte_mempool_get(cea_main_lcore_conf[lcore_id].de_conf.cmd_pool,
(VOID_P
*) &new_work); // mempools are created one for each
logical core
if (((uint64_t)(new_work)) < 0x7f0000000000)
printf("Result %d, lcore di partenza %u, lcore
di ricezione
%u, pointer %p\n", result, rte_lcore_id(), lcore_id,
new_work); //
debug print, on my server it should never happen but with
multi-thread
happens always on the last logical core!!!!
Here, checking the value of new_work looks wrong to me, before
ensuring that result == 0. At least, new_work should be set to
NULL before calling rte_mempool_get().
I put the check after result == 0, and just before the
rte_mempool_get() I set new_work to NULL, but nothing changed.
The first time something goes wrong the print is
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
635, pointer 0x880002
Sorry for the italian language print :) it means that
application is sending a message from the logical core 1 to the
logical core 2, it's the 635th time, the result is 0 and the
pointer is 0x880002 while all pointers before were 0x7ffxxxxxx.
One strange thing is that this behaviour happens always from the
logical core 1 to the logical core 2 when the counter is 635!!!
(Sending messages from 2 to 1 or 1 to 1 or 2 to 2 is all ok)
Another strange thing is that pointers from counter 636 to 640
are NULL, and from 641 begin again to be good... as you can see
here following (I attached the result of a test without the "if"
of the check on the value of new_work, and only for messages
from the lcore 1 to lcore 2)
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
627, pointer 0x7ffe8a261880
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
628, pointer 0x7ffe8a261900
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
629, pointer 0x7ffe8a261980
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
630, pointer 0x7ffe8a261a00
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
631, pointer 0x7ffe8a261a80
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
632, pointer 0x7ffe8a261b00
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
633, pointer 0x7ffe8a261b80
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
634, pointer 0x7ffe8a261c00
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
635, pointer 0x880002
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
636, pointer (nil)
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
637, pointer (nil)
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
638, pointer (nil)
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
639, pointer (nil)
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
640, pointer (nil)
This sure does seem like a memory over write problem, with maybe
a memset(0) in the mix as well. Have you tried using hardware
break points with the 0x880002 or 0x00 being written into this
range?
I put some breakpoints and found this:
1 - using pointer 0x880002, the output is (the pointer comes in
the middle of two rwlock):
(gdb) awatch *0x880002
Hardware access (read/write) watchpoint 1: *0x880002
(gdb) c
Continuing.
[New Thread 0x7fffeded5700 (LWP 19969)]
[New Thread 0x7fffed6d4700 (LWP 19970)]
[New Thread 0x7fffeced3700 (LWP 19971)]
[New Thread 0x7fffec6d2700 (LWP 19972)]
[New Thread 0x7fffebed1700 (LWP 19973)]
[New Thread 0x7fffeb6d0700 (LWP 19974)]
Hardware access (read/write) watchpoint 1: *0x880002
Value = 0
rte_rwlock_init (rwl=0x880000 <ikco_sdkif_actlist_lock+677024>)
at
/usr/share/dpdk/x86_64-default-linuxapp-gcc/include/generic/rte_rwlock.h:81
81 }
(gdb) c
Continuing.
Hardware access (read/write) watchpoint 1: *0x880002
These are most likely false positive hits and not the issue.
Value = 0
rte_rwlock_init (rwl=0x880004 <ikco_sdkif_actlist_lock+677028>)
at
/usr/share/dpdk/x86_64-default-linuxapp-gcc/include/generic/rte_rwlock.h:81
81 }
(gdb) c
Continuing.
2 - when using pointers minor or equal than 0x7ffe8a261d64 (in the
range of the mempool), gdb tells nothing about them (I don't use
them, I just get them from the pool and the put them in the pool
again);
3 - when using pointer 0x7ffe8a261d65 or greater, this is the
output of gdb:
(gdb) awatch *(int *)0x7ffe8a261d65
Hardware access (read/write) watchpoint 1: *(int *)0x7ffe8a261d65
(gdb) c
Continuing.
[New Thread 0x7fffeded5700 (LWP 17689)]
[New Thread 0x7fffed6d4700 (LWP 17690)]
[New Thread 0x7fffeced3700 (LWP 17691)]
[New Thread 0x7fffec6d2700 (LWP 17692)]
[New Thread 0x7fffebed1700 (LWP 17693)]
[New Thread 0x7fffeb6d0700 (LWP 17694)]
Hardware access (read/write) watchpoint 1: *(int *)0x7ffe8a261d65
Value = 0
0x00007ffff3798c21 in mempool_add_elem
(mp=mp@entry=0x7ffebfd8d6c0, obj=obj@entry=0x7ffe8a261d80,
iova=iova@entry=4465237376) at
/usr/src/debug/dpdk-17.11/lib/librte_mempool/rte_mempool.c:140
140 STAILQ_INSERT_TAIL(&mp->elt_list, hdr, next);
(gdb) where
#0 0x00007ffff3798c21 in mempool_add_elem
(mp=mp@entry=0x7ffebfd8d6c0, obj=obj@entry=0x7ffe8a261d80,
iova=iova@entry=4465237376) at
/usr/src/debug/dpdk-17.11/lib/librte_mempool/rte_mempool.c:140
#1 0x00007ffff37990f0 in rte_mempool_populate_iova
(mp=0x7ffebfd8d6c0, vaddr=0x7ffe8a23d540 "",
iova=4465087808, len=8388480, free_cb=<optimized out>,
opaque=<optimized out>)
at
/usr/src/debug/dpdk-17.11/lib/librte_mempool/rte_mempool.c:424
#2 0x00007ffff379967d in rte_mempool_populate_default
(mp=mp@entry=0x7ffebfd8d6c0)
at
/usr/src/debug/dpdk-17.11/lib/librte_mempool/rte_mempool.c:624
#3 0x00007ffff3799e89 in rte_mempool_create (name=<optimized
out>, n=<optimized out>,
elt_size=<optimized out>, cache_size=<optimized out>,
private_data_size=<optimized out>,
mp_init=0x7ffff444e410 <rte_pktmbuf_pool_init>, mp_init_arg=0x0,
obj_init=0x7ffff444e330 <rte_pktmbuf_init>, obj_init_arg=0x0,
socket_id=0, flags=0)
at
/usr/src/debug/dpdk-17.11/lib/librte_mempool/rte_mempool.c:952
#4 0x0000000000548a52 in main (argc=16, argv=0x7fffffffe3c8)
at
/root/gemini-cea-4.6.0/msrc/sys/com/linux-dpdk/cea-app/../../../../sys/com/linux-dpdk/cea-app/main.c:2360
(gdb) c
Continuing.
Hardware access (read/write) watchpoint 1: *(int *)0x7ffe8a261d65
This seems to be just creating a pktmbuf pool. The
STAILQ_INSERT_TAILQ is just putting the mempool on the main tailq
list for mempools in DPDK.
Old value = 0
New value = -402653184
0x00007ffff3798c24 in mempool_add_elem
(mp=mp@entry=0x7ffebfd8d6c0, obj=obj@entry=0x7ffe8a261e00,
iova=iova@entry=4465237504) at
/usr/src/debug/dpdk-17.11/lib/librte_mempool/rte_mempool.c:140
140 STAILQ_INSERT_TAIL(&mp->elt_list, hdr, next);
(gdb) where
#0 0x00007ffff3798c24 in mempool_add_elem
(mp=mp@entry=0x7ffebfd8d6c0, obj=obj@entry=0x7ffe8a261e00,
iova=iova@entry=4465237504) at
/usr/src/debug/dpdk-17.11/lib/librte_mempool/rte_mempool.c:140
#1 0x00007ffff37990f0 in rte_mempool_populate_iova
(mp=0x7ffebfd8d6c0, vaddr=0x7ffe8a23d540 "",
iova=4465087808, len=8388480, free_cb=<optimized out>,
opaque=<optimized out>)
at
/usr/src/debug/dpdk-17.11/lib/librte_mempool/rte_mempool.c:424
#2 0x00007ffff379967d in rte_mempool_populate_default
(mp=mp@entry=0x7ffebfd8d6c0)
at
/usr/src/debug/dpdk-17.11/lib/librte_mempool/rte_mempool.c:624
#3 0x00007ffff3799e89 in rte_mempool_create (name=<optimized
out>, n=<optimized out>,
elt_size=<optimized out>, cache_size=<optimized out>,
private_data_size=<optimized out>,
mp_init=0x7ffff444e410 <rte_pktmbuf_pool_init>, mp_init_arg=0x0,
obj_init=0x7ffff444e330 <rte_pktmbuf_init>, obj_init_arg=0x0,
socket_id=0, flags=0)
at
/usr/src/debug/dpdk-17.11/lib/librte_mempool/rte_mempool.c:952
#4 0x0000000000548a52 in main (argc=16, argv=0x7fffffffe3c8)
at
/root/gemini-cea-4.6.0/msrc/sys/com/linux-dpdk/cea-app/../../../../sys/com/linux-dpdk/cea-app/main.c:2360
(gdb) c
Continuing.
What do you think? It is normal that the mempool_add_elem is
called only on certain pointers of the mempool?
I attached the initialization of the mempool. Can this be wrong?
All mempools with a cache size will have two queue to put memory
on, one is the per lcore list and that one is used as a fast access
queue. When the cache becomes empty or has more entries then the
cache was created with then it pushed the extra entries to the main
list of mempool data.
Why do you say "mempools with a cache size" ? In my initialization
this mempool has cache_size = 0
If you give a cache size then you will have a cache list per lcore,
in your case you do not have a cache. BTW not having a cache will
effect performance a great deal.
The only time that rwlock is touched is to get/put items on the
main mempool.
Just as a data point have you tried this app on 18.08 yet? I do not
see the problem yet, sorry.
I'll try 18.08 and let you know
Hi ,
I tried 18.08 but nothing changed about the described behaviour. I'm
thinking about some overflow in my code lines but using valgrind on my
application tells me nothing more and it seems strange to me.
Is there any particular way to debug memory issues on dpdk application
apart from valgrind?
Regards,
Matteo
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
641, pointer 0x7ffe8a262b00
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
642, pointer 0x7ffe8a262b80
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
643, pointer 0x7ffe8a262d00
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
644, pointer 0x7ffe8a262d80
Result 0, lcore di partenza 1, lcore di ricezione 2, counter
645, pointer 0x7ffe8a262e00
if (result == 0)
{
new_work->command = command; // usage of the
memory gotten
from the mempool... <<<<<- here is where the application
crashes!!!!
Do you know why it crashes? Is it that new_work is NULL?
The pointer is not NULL but is not sequential to the others
(0x880002 as written before in this email). It seems to be in a
memory zone not in DPDK hugepages or something similar.
If I use this pointer the application crashes.
Can you check how the mempool is initialized? It should be in
multi
consumer and depending on your use case, single or multi producer.
Here is the initialization of this mempool
cea_main_cmd_pool[i] = rte_mempool_create(pool_name,
(unsigned int) (ikco_cmd_buffers - 1), // 65536 - 1
in this case
sizeof (CEA_DECODE_CMD_T), // 24 bytes
0, 0,
rte_pktmbuf_pool_init, NULL,
rte_pktmbuf_init, NULL,
rte_socket_id(), 0);
Another thing that could be checked: at all the places where you
return your work object to the mempool, you should add a check
that it is not NULL. Or just enabling RTE_LIBRTE_MEMPOOL_DEBUG
could do the trick: it adds some additional checks when doing
mempool operations.
I think I have already answered this point with the prints up in
the email.
What do you think about this behaviour?
Regards,
Matteo
result =
rte_ring_enqueue(cea_main_lcore_conf[lcore_id].de_conf.cmd_ring,
(VOID_P) new_work); // enqueues the gotten buffer on the
rings of all
lcores
// check on result value ...
}
else
{
// do something if result != 0 ...
}
}
This code worked perfectly (never had an issue) on
dpdk-2.2.0, while if
I use more than 1 thread doing these operations on dpdk-17.11
it happens
that after some times the "new_work" pointer is not a good
one, and the
application crashes when using that pointer.
It seems that these lines cannot be used by more than one thread
simultaneously. I also used many 2017 and 2018 dpdk versions
without
success.
Is this code possible on the new dpdk versions? Or have I to
change my
application so that this code is called just by one lcore at
a time?
Assuming the mempool is properly initialized, I don't see any
reason
why it would not work. There has been a lot of changes in
mempool between
dpdk-2.2.0 and dpdk-17.11, but this behavior should remain the
same.
If the comments above do not help to solve the issue, it could
be helpful
to try to reproduce the issue in a minimal program, so we can
help to
review it.
Regards,
Olivier
Regards,
Keith
Regards,
Matteo
Regards,
Keith
Regards,
Matteo
Regards,
Keith
