Re: RFC: using NIC DMA ring as tracing buffer?

Mathieu Desnoyers <[email protected]> Tue, 16 Apr 2024 10:48:57 -0400

Newsgroups	org.kernel.vger.linux-trace-users,org.kernel.vger.linux-trace-devel
Message-ID	<[email protected]>

On 2024-04-16 10:41, Alexander Aring wrote:
> Hi all,
> 
> I have an idea about using the DMA rings of a networking card as a
> tracing buffer. 

The first thing I'd be worried about is overhead caused by
false-sharing if you trace a large SMP/many-core system all
into the same global NIC buffer. The cache lines will bounce
left and right which is bad performance-wise.

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com