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Re: [Qemu-devel] [PATCH] do not send packet to nic if the packet will be
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From: |
Kevin Wolf |
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Subject: |
Re: [Qemu-devel] [PATCH] do not send packet to nic if the packet will be dropped by nic |
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Date: |
Mon, 20 Jun 2011 11:52:20 +0200 |
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User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10 |
Am 20.06.2011 11:40, schrieb Wen Congyang:
> At 06/20/2011 05:10 PM, Kevin Wolf Write:
>> Am 17.06.2011 03:33, schrieb Wen Congyang:
>>> If !s->clock_enabled or !rtl8139_receiver_enabled(s), it means that
>>> the nic will drop all packets from host. So qemu will keep getting
>>> packets from host and wasting CPU on dropping packets. This seems
>>> worse than packets that should be dropped but aren't.
>>>
>>> Signed-off-by: Wen Congyang <address@hidden>
>>
>> Which bug does this change fix? I'm still not convinced that we should
>> do it.
>
> Maybe not a bug fix now. As Michael S. Tsirkin said, if rtl8139_can_receive()
> returns 1, qemu will keep getting packets from host and wasting CPU on
> dropping packets. We can save CPU by return 0.
Don't we waste memory instead then because we leave the packets queued
indefinitely?
Kevin
Re: [Qemu-devel] [PATCH] fix the return value of rtl8139_can_receive(), Wen Congyang, 2011/06/16