From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
To: Chaitanya Kulkarni <chaitanyak@nvidia.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"michael.christie@oracle.com" <michael.christie@oracle.com>,
"kernel-janitors@vger.kernel.org"
<kernel-janitors@vger.kernel.org>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"target-devel@vger.kernel.org" <target-devel@vger.kernel.org>,
"Martin K. Petersen" <martin.petersen@oracle.com>
Subject: Re: [PATCH v2] scsi: target: Save a few cycles in transport_lookup_[cmd|tmr]_lun()
Date: Tue, 16 Aug 2022 10:12:25 +0200 [thread overview]
Message-ID: <b6025226-4fcd-1d82-60eb-301734cc8e5a@wanadoo.fr> (raw)
In-Reply-To: <757f1326-bc70-aa93-b2d3-dfd91698406e@nvidia.com>
Le 16/08/2022 à 08:06, Chaitanya Kulkarni a écrit :
> On 8/15/22 13:52, Christophe JAILLET wrote:
>> Use percpu_ref_tryget_live_rcu() instead of percpu_ref_tryget_live() to
>> save a few cycles when it is known that the rcu lock is already
>> taken/released.
>>
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
>> ---
> do you have a quantitative data that shows actual savings of cycles?
>
> -ck
>
Some numbers were given for io_uring by the one who introduced
percpu_ref_tryget_live_rcu().
See [1].
I don't have specific numbers for the patch against scsi.
CJ
[1]:
https://lore.kernel.org/linux-kernel/cover.1634822969.git.asml.silence@gmail.com/
prev parent reply other threads:[~2022-08-16 10:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-15 20:52 Christophe JAILLET
2022-08-16 6:06 ` Chaitanya Kulkarni
2022-08-16 8:12 ` Christophe JAILLET [this message]
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