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From: | Cao jin |
Subject: | Re: [Qemu-trivial] [PATCH] qemu-timer: remove unnecessary code |
Date: | Wed, 13 Jul 2016 20:13:35 +0800 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 |
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
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