From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?= Date: Tue, 8 Sep 2020 07:38:38 +0200 Subject: [Intel-wired-lan] [PATCH bpf-next 4/4] ixgbe, xsk: use XSK_NAPI_WEIGHT as NAPI poll budget In-Reply-To: <20200907123241.447371e8@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> References: <20200907150217.30888-1-bjorn.topel@gmail.com> <20200907150217.30888-5-bjorn.topel@gmail.com> <20200907123241.447371e8@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: On 2020-09-07 21:32, Jakub Kicinski wrote: > On Mon, 7 Sep 2020 17:02:17 +0200 Bj?rn T?pel wrote: >> From: Bj?rn T?pel >> >> Start using XSK_NAPI_WEIGHT as NAPI poll budget for the AF_XDP Rx >> zero-copy path. >> >> Signed-off-by: Bj?rn T?pel >> --- >> drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c >> index 3771857cf887..f32c1ba0d237 100644 >> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c >> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c >> @@ -239,7 +239,7 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector, >> bool failure = false; >> struct sk_buff *skb; >> >> - while (likely(total_rx_packets < budget)) { >> + while (likely(total_rx_packets < XSK_NAPI_WEIGHT)) { > > I was thinking that we'd multiply 'budget' here, not replace it with a > constant. Looks like ixgbe dutifully passes 'per_ring_budget' into the > clean_rx functions, not a complete NAPI budget. > Correct, and i40e/ice does the same ("per_ring_budget"). As for budget << XSK_NAPI_MULT vs replacing; Replacing the budget is more in line with what the drivers do for the Tx cleanup (xxx_clean_tx_irq), where the napi budget is discarded completely; Again, with the idea that "this is much cheaper than a "per-packet through the stack". Do you prefer the multiplier way that you describe? Cheers, Bj?rn >> union ixgbe_adv_rx_desc *rx_desc; >> struct ixgbe_rx_buffer *bi; >> unsigned int size; >