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Re: [Qemu-devel] [PATCH v2] hw/net/opencores_eth: Allocating Large sized
From: |
Max Filippov |
Subject: |
Re: [Qemu-devel] [PATCH v2] hw/net/opencores_eth: Allocating Large sized arrays to heap |
Date: |
Wed, 27 Apr 2016 05:46:26 +0300 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
Hi Zhou,
On Wed, Apr 27, 2016 at 10:18:56AM +0800, Zhou Jie wrote:
> When I committed another patch which named as
> "hw/net/virtio-net: Allocating Large sized arrays to heap" .
>
> Christian Borntraeger said that 16k is usually perfectly fine
> for a userspace stack and doing allocations in a hot path
> might actually hurt performance.
>
> Although the size is 65536 bytes here,
> I think open_eth_start_xmit is in a hot path.
> So, it is OK, if you think that this patch should not be applied.
With Linux as guest OS we shouldn't see any allocations
as it doesn't send huge packets, so I think this patch is fine.
I can take it through the xtensa tree if you don't have other
plan.
--
Thanks.
-- Max