From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
To: "Morten Brørup" <mb@smartsharesystems.com>,
olivier.matz@6wind.com, dev@dpdk.org
Cc: honnappa.nagarahalli@arm.com, bruce.richardson@intel.com,
konstantin.ananyev@huawei.com
Subject: Re: [PATCH v3] mempool: micro-optimize put function
Date: Tue, 27 Dec 2022 11:54:08 +0300 [thread overview]
Message-ID: <d4ecb116-edcd-1656-d541-707da08910d8@oktetlabs.ru> (raw)
In-Reply-To: <20221224104630.32235-1-mb@smartsharesystems.com>
On 12/24/22 13:46, Morten Brørup wrote:
> Micro-optimization:
> Reduced the most likely code path in the generic put function by moving an
> unlikely check out of the most likely code path and further down.
>
> Also updated the comments in the function.
>
> v3 (feedback from Konstantin Ananyev):
> * Removed assertion and comment about the invariant preventing overflow
> in the comparison. They were more confusing than enlightening.
> v2 (feedback from Andrew Rybchenko):
> * Modified comparison to prevent overflow if n is really huge and len is
> non-zero.
> * Added assertion about the invariant preventing overflow in the
> comparison.
> * Crossing the threshold is not extremely unlikely, so removed likely()
> from that comparison.
> The compiler will generate code with optimal static branch prediction
> here anyway.
>
> Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
> Acked-by: Konstantin Ananyev <konstantin.ananyev@huawei.com>
Thanks for optimizing it further.
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---
> lib/mempool/rte_mempool.h | 35 ++++++++++++++++++-----------------
> 1 file changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/lib/mempool/rte_mempool.h b/lib/mempool/rte_mempool.h
> index 9f530db24b..61ca0c6b65 100644
> --- a/lib/mempool/rte_mempool.h
> +++ b/lib/mempool/rte_mempool.h
> @@ -1364,32 +1364,33 @@ rte_mempool_do_generic_put(struct rte_mempool *mp, void * const *obj_table,
> {
> void **cache_objs;
>
> - /* No cache provided */
> + /* No cache provided? */
IMHO such changes do not add value and just add noise.
There are few similar cases below.
No strong opinion in any case.
next prev parent reply other threads:[~2022-12-27 8:54 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-16 10:18 [PATCH] " Morten Brørup
2022-11-16 11:04 ` Andrew Rybchenko
2022-11-16 11:10 ` Morten Brørup
2022-11-16 11:29 ` Andrew Rybchenko
2022-11-16 12:14 ` [PATCH v2] " Morten Brørup
2022-11-16 15:51 ` Honnappa Nagarahalli
2022-11-16 15:59 ` Morten Brørup
2022-11-16 16:26 ` Honnappa Nagarahalli
2022-11-16 17:39 ` Morten Brørup
2022-12-19 8:50 ` Morten Brørup
2022-12-22 13:52 ` Konstantin Ananyev
2022-12-22 15:02 ` Morten Brørup
2022-12-23 16:34 ` Konstantin Ananyev
2022-12-24 10:46 ` [PATCH v3] " Morten Brørup
2022-12-27 8:54 ` Andrew Rybchenko [this message]
2022-12-27 15:37 ` Morten Brørup
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