[dpdk-users] Need your help on pdump

Pattan, Reshma reshma.pattan at intel.com
Tue Feb 7 14:48:11 CET 2017


Please see my comments inline.


From: Clarylin L [mailto:clearasu at gmail.com]
Sent: Friday, February 3, 2017 7:54 PM
To: Pattan, Reshma <reshma.pattan at intel.com>
Subject: Need your help on pdump

Hi Reshma,

I am currently working on dpdk pdump and got some issues with it. Tried to research online but there were not many documents/discussions on it. On the mailing list I found you have been helping with someone on pdump, so drop you this email trying to seek help.

1.     I believe dpdk-pdump would take hugepages. However, number of free hugepages does not change at all after dpdk-pdump start running. Is this expected?  for example, before starting dpdk-pdump, I have

[Reshma]: dpdk-pdump is a secondary process hence itself will not take any huge pages, instead it will be attached to the same huge page memory of the primary process.

host# cat /proc/meminfo | grep uge

AnonHugePages:    712704 kB

HugePages_Total:    1336

HugePages_Free:      661

HugePages_Rsvd:        0

HugePages_Surp:        0

Hugepagesize:       2048 kB

After dpdk-pdump starts (and it's running fine), the numbers remain the same.

2.       Since Hugepages do not change, it gives me no hint when "cannot reserve memory" error comes up on some system. Generally this error is due to insufficient hugepages. However, the system shows

[Reshma]: Though huge pages are available the reason for cannot reserve memory could be because they are not contiguous huge pages.

Please check the section in http://dpdk.org/doc/guides/linux_gsg/sys_reqs.html to allocate contiguous huge pages.

host# cat /proc/meminfo | grep uge

AnonHugePages:   1036288 kB

HugePages_Total:     768

HugePages_Free:      376

HugePages_Rsvd:        0

HugePages_Surp:        0

Hugepagesize:       2048 kB

3. Even when dpdk-pdump is running fine, I got quite a few "PDUMP: User mempool: insufficient data_len of mbuf "messages on the server side. I tried to increase the mbuf-size for dpdk-pdump and it didn't fix it.

[Reshma]: The mbuf size option that you pass to the dpdk-pdump command line option should be equal or greater than the packet size (This is related to the internals of design) .

So I suggest you try once again with enough size.

Appreciate your help. Thanks a lot.


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