From: Cao jin <caoj.fnst@cn.fujitsu.com>
To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org
Cc: qemu-trivial@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] qemu-timer: remove unnecessary code
Date: Wed, 13 Jul 2016 20:13:35 +0800 [thread overview]
Message-ID: <5786306F.6080503@cn.fujitsu.com> (raw)
In-Reply-To: <aaf97fcf-e706-7305-08a0-3c1e99887456@redhat.com>
On 07/13/2016 07:40 PM, Paolo Bonzini wrote:
>
>
> On 13/07/2016 13:40, Cao jin wrote:
>>
>>
>> On 07/13/2016 06:21 PM, Paolo Bonzini wrote:
>>>
>>>
>>> On 13/07/2016 11:06, Cao jin wrote:
>>>> When passed argument 'ns' is 0, macro DIV_ROUND_UP will return 0 also.
>>>
>>> It's potentially slower though.
>>>
>>
>> Is it because the function in the i/o loop path, so the potentially
>> extra arithmetical instructions matters?
>
> It is quite common for ns to be zero, for example if a bottom half has
> to be invoked.
>
I see. I need dig deeper to understand the wholely I/O mechanism. Thanks
Paolo!
> However, qemu_timeout_ns_to_ms is not used in the really important path
> (which is aio_poll in aio-posix.c) so I guess your patch is okay.
>
> Thanks,
>
> Paolo
>
--
Yours Sincerely,
Cao jin
prev parent reply other threads:[~2016-07-13 12:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-13 9:06 [Qemu-devel] [PATCH] qemu-timer: remove unnecessary code Cao jin
2016-07-13 10:21 ` Paolo Bonzini
2016-07-13 11:40 ` Cao jin
2016-07-13 11:40 ` Paolo Bonzini
2016-07-13 12:13 ` Cao jin [this message]
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