| Message ID | 20210319040447.527-1-liew.s.piaw@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | atl1c: optimize rx loop | expand |
On Fri, Mar 19, 2021 at 05:15:35AM +0100, Willy Tarreau wrote: > On Fri, Mar 19, 2021 at 12:04:47PM +0800, Sieng Piaw Liew wrote: > > Remove this trivial bit of inefficiency from the rx receive loop, > > results in increase of a few Mbps in iperf3. Tested on Intel Core2 > > platform. > > > > Signed-off-by: Sieng Piaw Liew <liew.s.piaw@gmail.com> > > --- > > drivers/net/ethernet/atheros/atl1c/atl1c_main.c | 4 +--- > > 1 file changed, 1 insertion(+), 3 deletions(-) > > > > diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c > > index 3f65f2b370c5..b995f9a0479c 100644 > > --- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c > > +++ b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c > > @@ -1796,9 +1796,7 @@ static void atl1c_clean_rx_irq(struct atl1c_adapter *adapter, > > struct atl1c_recv_ret_status *rrs; > > struct atl1c_buffer *buffer_info; > > > > - while (1) { > > - if (*work_done >= work_to_do) > > - break; > > + while (*work_done < work_to_do) { > > It should not change anything, or only based on the compiler's optimization > and should not result in a measurable difference because what it does is > exactly the same. Have you really compared the compiled output code to > explain the difference ? I strongly suspect you'll find no difference at > all. > > Thus for me it's certainly not an optimization, it could be qualified as > a cleanup to improve code readability however. > > Willy You're right. Objdump and diff showed no difference. Regards, Sieng Piaw
diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c index 3f65f2b370c5..b995f9a0479c 100644 --- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c +++ b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c @@ -1796,9 +1796,7 @@ static void atl1c_clean_rx_irq(struct atl1c_adapter *adapter, struct atl1c_recv_ret_status *rrs; struct atl1c_buffer *buffer_info; - while (1) { - if (*work_done >= work_to_do) - break; + while (*work_done < work_to_do) { rrs = ATL1C_RRD_DESC(rrd_ring, rrd_ring->next_to_clean); if (likely(RRS_RXD_IS_VALID(rrs->word3))) { rfd_num = (rrs->word0 >> RRS_RX_RFD_CNT_SHIFT) &
Remove this trivial bit of inefficiency from the rx receive loop, results in increase of a few Mbps in iperf3. Tested on Intel Core2 platform. Signed-off-by: Sieng Piaw Liew <liew.s.piaw@gmail.com> --- drivers/net/ethernet/atheros/atl1c/atl1c_main.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)