From: Stefano Brivio <sbrivio@redhat.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: passt-dev@passt.top
Subject: Re: [PATCH 3/5] tap: Don't use EPOLLET on Qemu sockets
Date: Fri, 26 Jul 2024 10:00:56 +0200 [thread overview]
Message-ID: <20240726100056.235b65de@elisabeth> (raw)
In-Reply-To: <20240726072031.3941305-4-david@gibson.dropbear.id.au>
On Fri, 26 Jul 2024 17:20:29 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:
> Currently we set EPOLLET (edge trigger) on the epoll flags for the
> connected Qemu Unix socket. It's not clear that there's a reason for
> doing this: for TCP sockets we need to use EPOLLET, because we leave data
> in the socket buffers for our flow control handling. That consideration
> doesn't apply to the way we handle the qemu socket however.
It significantly decreases epoll_wait() overhead on sustained data
transfers, because we can read multiple TAP_BUF_SIZE buffers at a time
instead of just one.
I can check that now again with current QEMU and kernel versions, plus
several fundamental changes in buffer handling, but I don't see a real
reason why this shouldn't have changed meanwhile.
--
Stefano
next prev parent reply other threads:[~2024-07-26 8:01 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-26 7:20 [PATCH 0/5] Fix assorted errors in the Qemu socket tap receive handler David Gibson
2024-07-26 7:20 ` [PATCH 1/5] tap: Better report errors receiving from QEMU socket David Gibson
2024-07-26 11:25 ` Stefano Brivio
2024-07-26 11:50 ` Stefano Brivio
2024-07-26 12:02 ` David Gibson
2024-07-26 7:20 ` [PATCH 2/5] tap: Don't attempt to carry on if we get a bad frame length from qemu David Gibson
2024-07-26 11:26 ` Stefano Brivio
2024-07-26 7:20 ` [PATCH 3/5] tap: Don't use EPOLLET on Qemu sockets David Gibson
2024-07-26 8:00 ` Stefano Brivio [this message]
2024-07-26 10:44 ` Stefano Brivio
2024-07-26 12:12 ` David Gibson
2024-07-26 13:25 ` Stefano Brivio
2024-07-29 1:15 ` David Gibson
2024-07-26 7:20 ` [PATCH 4/5] tap: Correctly handle frames of odd length David Gibson
2024-07-26 7:20 ` [PATCH 5/5] tap: Improve handling of partially received frames on qemu socket David Gibson
2024-07-26 11:39 ` Stefano Brivio
2024-07-26 12:33 ` David Gibson
2024-07-26 13:19 ` [PATCH 0/5] Fix assorted errors in the Qemu socket tap receive handler Stefano Brivio
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