On 1/27/2021 2:08 PM, Liron Himi wrote:


Liron Himi
Staff Software Engineer

Park Azorim, Kyriat Arie, Petah Tikva, 49527, Israel
Mobile: +972.52.3329169

-----Original Message-----
From: Ferruh Yigit <ferruh.yi...@intel.com>
Sent: Wednesday, 27 January 2021 01:50
To: Liron Himi <lir...@marvell.com>; Jerin Jacob Kollanukkaran 
<jer...@marvell.com>
Cc: dev@dpdk.org
Subject: [EXT] Re: [dpdk-dev] [PATCH v2 26/37] net/mvpp2: introduce fixup for 
fifo overrun

External Email

----------------------------------------------------------------------
On 1/22/2021 7:19 PM, lir...@marvell.com wrote:
From: Liron Himi <lir...@marvell.com>

Currently the HW is configured with only one pool which its buffer
size may be larger than the rx-fifo-size.
In that situation, frame size larger than the fifo-size is gets
dropped due to fifo overrun.
this is cause because the HW works in cut-through mode which waits to
have in the fifo at least the amount of bytes as define in the
smallest pool's buffer size.

This patch add a dummy pool which its buffer size is very small
(smaller than 64B frame). this tricks the HW and any frame size is
gets passed from the FIFO to the PP2.

Signed-off-by: Liron Himi <lir...@marvell.com>

so this is fixing the FIFO overrun, can you please provide the fixes line?
[L.H.] it is kind of combination of HW fifo size (which defined by kernel 
driver), given buffer size and incoming pkt size. I don't think I can point to 
a line in DPDK driver code that this patch is fixing.
it is a kind of WA for a HW issue.


Is HW FIFO size or HW behavior (to wait at least smallest pool's buffer size) changed with recent kernel driver or MUSDK to cause this problem? If so can you please mention/reference that change in the commit log?

And should this patch backported?
[L.H.] it cannot be backported as it depends on MUSDK api change.


Is the fix or problem depends on the MUSDK API change? If the fix has a dependency will this be a problem, since it means latest driver won't be usable with old MUSDK version?
Can you please clarify the dependency in the commit log?

Thanks,
ferruh

Reply via email to