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[76.102.12.149]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2b170673bc0sm21277584eec.5.2026.01.14.12.57.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Jan 2026 12:57:16 -0800 (PST) Date: Wed, 14 Jan 2026 12:57:15 -0800 From: Stanislav Fomichev To: Jason Xing Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, bjorn@kernel.org, magnus.karlsson@intel.com, maciej.fijalkowski@intel.com, jonathan.lemon@gmail.com, sdf@fomichev.me, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, bpf@vger.kernel.org, netdev@vger.kernel.org, Jason Xing Subject: Re: [PATCH net-next v6 2/2] xsk: move cq_cached_prod_lock to avoid touching a cacheline in sending path Message-ID: References: <20260104012125.44003-1-kerneljasonxing@gmail.com> <20260104012125.44003-3-kerneljasonxing@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On 01/13, Jason Xing wrote: > On Sun, Jan 4, 2026 at 9:21 AM Jason Xing wrote: > > > > From: Jason Xing > > > > We (Paolo and I) noticed that in the sending path touching an extra > > cacheline due to cq_cached_prod_lock will impact the performance. After > > moving the lock from struct xsk_buff_pool to struct xsk_queue, the > > performance is increased by ~5% which can be observed by xdpsock. > > > > An alternative approach [1] can be using atomic_try_cmpxchg() to have the > > same effect. But unfortunately I don't have evident performance numbers to > > prove the atomic approach is better than the current patch. The advantage > > is to save the contention time among multiple xsks sharing the same pool > > while the disadvantage is losing good maintenance. The full discussion can > > be found at the following link. > > > > [1]: https://lore.kernel.org/all/20251128134601.54678-1-kerneljasonxing@gmail.com/ > > > > Suggested-by: Paolo Abeni > > Signed-off-by: Jason Xing > > Hi Magnus, Maciej and Stanislav, > > Any feedback on the whole series? LGTM, thanks! (I'm gonna be a bit slow on the mailing list in Jan/Feb)