This tool seems awesome!!! Better than VTUNE? On Thu, May 19, 2022 at 10:29 AM Kinsella, Ray <[email protected]> wrote:
> I’d say that is likely yes. > > > > FYI - pcm-memory is very handy tool for looking at memory traffic. > > https://github.com/opcm/pcm > > > > Thanks, > > > > Ray K > > > > *From:* Sanford, Robert <[email protected]> > *Sent:* Wednesday 18 May 2022 17:53 > *To:* Antonio Di Bacco <[email protected]>; [email protected] > *Subject:* Re: DPDK performances surprise > > > > My guess is that most of the packet data has a short life in the L3 cache > (before being overwritten by newer packets), but is never flushed to memory. > > > > *From: *Antonio Di Bacco <[email protected]> > *Date: *Wednesday, May 18, 2022 at 12:40 PM > *To: *"[email protected]" <[email protected]> > *Subject: *DPDK performances surprise > > > > I recently read a performance test where l2fwd was able to receive packets > (8000B) from a 100 Gbps card, swap the L2 addresses and send them back to > the same port to be received by an ethernet analyzer. The throughput > achieved was close to 100 Gbps on a XEON machine (Intel(R) Xeon(R) Platinum > 8176 CPU @ 2.10GHz) . This is the same processor I have and I know that, if > I try to write around 8000B to the attached DDR4 (2666MT/s) on an allocated > 1GB hugepage, I get a maximum throughput of around 20GB/s. > > > > Now, a 100 Gbps can generate a flow of around 12 GB/s, these packets have > to be written to the DDR and then read back to swap L2 addresses and this > leads to a cumulative bandwidth on the DDR that is around 2x12 GB/s and is > more than the 20GB/s of available bandwidth on the DDR4. > > > > How can this be possible ? >
