> -----Original Message----- > From: Jerin Jacob <[email protected]> > Sent: Wednesday, April 14, 2021 1:43 AM > To: Ruifeng Wang <[email protected]> > Cc: [email protected]; [email protected]; Ferruh Yigit > <[email protected]>; [email protected]; David Marchand > <[email protected]>; dpdk-dev <[email protected]>; nd > <[email protected]>; Honnappa Nagarahalli <[email protected]> > Subject: Re: [dpdk-dev] [PATCH 3/4] examples/l3fwd: eliminate unnecessary > reloads in loop > > On Thu, Mar 18, 2021 at 3:56 PM Ruifeng Wang <[email protected]> > wrote: > > > > Number of rx queue and number of rx port in lcore config are constants > > during the period of l3 forward application running. But compiler has > > no this information. > > > > Copied values from lcore config to local variables and used the local > > variables for iteration. Compiler can see that the local variables are > > not changed, so qconf reloads at each iteration can be eliminated. > > > > The change showed 1.8% performance uplift in single core, single port, > > single queue test on N1SDP platform with MLX5 NIC. > > At least, in octeontx2, I dont see any performance improvement. > But change looks good. Please find below a comment. > > > > > Signed-off-by: Ruifeng Wang <[email protected]> > > --- > > examples/l3fwd/l3fwd_lpm.c | 10 ++++++---- > > 1 file changed, 6 insertions(+), 4 deletions(-) > > > > diff --git a/examples/l3fwd/l3fwd_lpm.c b/examples/l3fwd/l3fwd_lpm.c > > index 3dcf1fef1..d338590b9 100644 > > --- a/examples/l3fwd/l3fwd_lpm.c > > +++ b/examples/l3fwd/l3fwd_lpm.c > > @@ -190,14 +190,16 @@ lpm_main_loop(__rte_unused void *dummy) > > lcore_id = rte_lcore_id(); > > qconf = &lcore_conf[lcore_id]; > > > > - if (qconf->n_rx_queue == 0) { > > + uint16_t n_rx_q = qconf->n_rx_queue; > > + uint16_t n_tx_p = qconf->n_tx_port; > > How about adding const?
Ack. The values are not expected to be changed. Will update in next version.
