From: Willy Tarreau <w@1wt.eu>
To: Sieng Piaw Liew <liew.s.piaw@gmail.com>
Cc: chris.snook@gmail.com, davem@davemloft.net, kuba@kernel.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] atl1c: optimize rx loop
Date: Fri, 19 Mar 2021 05:15:35 +0100 [thread overview]
Message-ID: <20210319041535.GA3441@1wt.eu> (raw)
In-Reply-To: <20210319040447.527-1-liew.s.piaw@gmail.com>
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
next prev parent reply other threads:[~2021-03-19 4:16 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-19 4:04 [PATCH] atl1c: optimize rx loop Sieng Piaw Liew
2021-03-19 4:15 ` Willy Tarreau [this message]
2021-03-22 0:54 ` Sieng Piaw Liew
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