From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <v.shpilevoy@tarantool.org>
Received: from smtpng3.m.smailru.net (smtpng3.m.smailru.net [94.100.177.149])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256
 bits)) (No client certificate requested)
 by dev.tarantool.org (Postfix) with ESMTPS id 23FA2445320
 for <tarantool-patches@dev.tarantool.org>;
 Sat, 11 Jul 2020 00:28:28 +0300 (MSK)
References: <20200710075605.217824-1-gorcunov@gmail.com>
 <20200710075605.217824-4-gorcunov@gmail.com>
 <9c941738-75ce-3357-1bdb-6af6b95a4db6@tarantool.org>
 <20200710211020.GI1999@grain>
From: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Message-ID: <66e76c8e-3c53-9336-9c37-48dee8fefee8@tarantool.org>
Date: Fri, 10 Jul 2020 23:28:26 +0200
MIME-Version: 1.0
In-Reply-To: <20200710211020.GI1999@grain>
Content-Type: text/plain; charset="utf-8"
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Subject: Re: [Tarantool-patches] [PATCH 3/5] qsync: txn_commit_async -- drop
 redundant variable
List-Id: Tarantool development patches <tarantool-patches.dev.tarantool.org>
List-Unsubscribe: <https://lists.tarantool.org/mailman/options/tarantool-patches>, 
 <mailto:tarantool-patches-request@dev.tarantool.org?subject=unsubscribe>
List-Archive: <https://lists.tarantool.org/pipermail/tarantool-patches/>
List-Post: <mailto:tarantool-patches@dev.tarantool.org>
List-Help: <mailto:tarantool-patches-request@dev.tarantool.org?subject=help>
List-Subscribe: <https://lists.tarantool.org/mailman/listinfo/tarantool-patches>, 
 <mailto:tarantool-patches-request@dev.tarantool.org?subject=subscribe>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: tml <tarantool-patches@dev.tarantool.org>

On 10/07/2020 23:10, Cyrill Gorcunov wrote:
> On Fri, Jul 10, 2020 at 10:35:50PM +0200, Vladislav Shpilevoy wrote:
>> Опять же. Патч технически корректен, но так же и бесполезен.
>> Его полезность сравнима с исправлением опечатки в каком-нибудь
>> не особо нужном комменте. Сори, если токсично звучит.
>>
>> Но не вижу в этом патче нужды.
> 
> We've to allocate a variable which we simply don't need. Look,
> the former code reads the flag, puts it into variable then
> immediately read it and that's all :/ I think we should not
> spread @is_sync but read the flag as much as possible for
> better grep'ability.

Do you have a proof that this change improves anything? That
the variable 'allocation' on the stack actually happens, and
costs even 1 ns?