On 6/23/2020 3:29 PM, Ciara Loftus wrote: > This commit makes some changes to the AF_XDP PMD in an effort to improve > its packet loss characteristics. > > 1. In the case of failed transmission due to inability to reserve a tx > descriptor, the PMD now pulls from the completion ring, issues a syscall > in which the kernel attempts to complete outstanding tx operations, then > tries to reserve the tx descriptor again. Prior to this we dropped the > packet after the syscall and didn't try to re-reserve. > > 2. During completion ring cleanup, always pull as many entries as possible > from the ring as opposed to the batch size or just how many packets > we're going to attempt to send. Keeping the completion ring emptier should > reduce failed transmissions in the kernel, as the kernel requires space in > the completion ring to successfully tx. > > 3. Size the fill ring as twice the receive ring size which may help reduce > allocation failures in the driver. > > 4. Emulate a tx_free_thresh - when the number of available entries in the > completion ring rises above this, we pull from it. The threshold is set to > 1k entries. > > With these changes, a benchmark which measured the packet rate at which > 0.01% packet loss could be reached improved from ~0.1G to ~3Gbps. > > Signed-off-by: Ciara Loftus <ciara.lof...@intel.com> > Acked-by: Xiaolong Ye <xiaolong...@intel.com>
Applied to dpdk-next-net/master, thanks.
