[PATCH] examples/l3fwd: optimize packet prefetch

[Stephen Hemminger]

On Wed, 25 Dec 2024 15:53:02 +0800
Dengdui Huang <huangdengdui at huawei.com> wrote:

> From: Dengdui Huang <huangdengdui at huawei.com>
> To: <dev at dpdk.org>
> CC: <wathsala.vithanage at arm.com>, <stephen at networkplumber.org>,  <liuyonglong at huawei.com>, <fengchengwen at huawei.com>, <haijie1 at huawei.com>,  <lihuisong at huawei.com>
> Subject: [PATCH] examples/l3fwd: optimize packet prefetch
> Date: Wed, 25 Dec 2024 15:53:02 +0800
> X-Mailer: git-send-email 2.33.0
> 
> The prefetch window depending on the hardware platform. The current prefetch
> policy may not be applicable to all platforms. In most cases, the number of
> packets received by Rx burst is small (64 is used in most performance reports).
> In L3fwd, the maximum value cannot exceed 512. Therefore, prefetching all
> packets before processing can achieve better performance.
> 
> Signed-off-by: Dengdui Huang <huangdengdui at huawei.com>
> ---

I think Vpp had a good description of how to unroll and deal with prefetch.

With larger burst sizes you don't want to prefetch the whole burst.