From: Stefano Brivio <sbrivio@redhat.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: passt-dev@passt.top
Subject: Re: [PATCH v3 00/18] RFC: Unify and simplify tap send path
Date: Mon, 13 Feb 2023 02:14:25 +0100 [thread overview]
Message-ID: <20230213021425.1d5edd76@elisabeth> (raw)
In-Reply-To: <20230126002133.7a8eec98@elisabeth>
On Thu, 26 Jan 2023 00:21:33 +0100
Stefano Brivio <sbrivio@redhat.com> wrote:
> On Wed, 25 Jan 2023 14:13:44 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
>
> > On Tue, Jan 24, 2023 at 10:20:43PM +0100, Stefano Brivio wrote:
> > > On Fri, 6 Jan 2023 11:43:04 +1100
> > > David Gibson <david@gibson.dropbear.id.au> wrote:
> > >
> > > > Although we have an abstraction for the "slow path" (DHCP, NDP) guest
> > > > bound packets, the TCP and UDP forwarding paths write directly to the
> > > > tap fd. However, it turns out how they send frames to the tap device
> > > > is more similar than it originally appears.
> > > >
> > > > This series unifies the low-level tap send functions for TCP and UDP,
> > > > and makes some clean ups along the way.
> > > >
> > > > This is based on my earlier outstanding series.
> > >
> > > For some reason, performance tests consistently get stuck (both TCP and
> > > UDP, sometimes throughput, sometimes latency tests) with this series,
> > > and not without it, but I don't see any possible relationship with that.
> >
> > Drat, I didn't encounter that. Any chance you could bisect to figure
> > out which patch specifically seems to trigger it?
>
> [...]
>
> > I wonder if this could be related to the stalls I'm debugging,
> > although those didn't appear on the perf tests and also occur on
> > main. I have now discovered they seem to be masked by large socket
> > buffer sizes - more info at https://bugs.passt.top/show_bug.cgi?id=41
>
> Maybe the subsequent failures (or even this one) could actually be
> related, and triggered somehow by some change in timing. I'm still
> clueless at the moment.
This turned out to be a combination of three different issues:
- left-over patches in my local qemu tree (and build) trying to address
the virtio-net TX hang ultimately fixed by kernel commit d71ebe8114b4
("virtio-net: correctly enable callback during start_xmit"). I'm using
the latest upstream now, clean
- the issue you reported at https://bugs.passt.top/show_bug.cgi?id=41,
I just posted a patch for it
- the issue introduced by "tcp: Combine two parts of pasta tap send path
together", patch also posted
With these three sorted, finally I could apply this series! Apologies
for the delay.
--
Stefano
prev parent reply other threads:[~2023-02-13 1:22 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-06 0:43 [PATCH v3 00/18] RFC: Unify and simplify tap send path David Gibson
2023-01-06 0:43 ` [PATCH v3 01/18] pcap: Introduce pcap_frame() helper David Gibson
2023-01-06 0:43 ` [PATCH v3 02/18] pcap: Replace pcapm() with pcap_multiple() David Gibson
2023-01-06 0:43 ` [PATCH v3 03/18] tcp: Combine two parts of passt tap send path together David Gibson
2023-01-06 0:43 ` [PATCH v3 04/18] tcp: Don't compute total bytes in a message until we need it David Gibson
2023-01-06 0:43 ` [PATCH v3 05/18] tcp: Improve interface to tcp_l2_buf_flush() David Gibson
2023-01-06 0:43 ` [PATCH v3 06/18] tcp: Combine two parts of pasta tap send path together David Gibson
2023-02-13 1:13 ` Stefano Brivio
2023-01-06 0:43 ` [PATCH v3 07/18] tap, tcp: Move tap send path to tap.c David Gibson
2023-01-06 0:43 ` [PATCH v3 08/18] util: Introduce hton*_constant() in place of #ifdefs David Gibson
2023-01-06 0:43 ` [PATCH v3 09/18] tcp, udp: Use named field initializers in iov_init functions David Gibson
2023-01-06 0:43 ` [PATCH v3 10/18] util: Parameterize ethernet header initializer macro David Gibson
2023-01-06 0:43 ` [PATCH v3 11/18] tcp: Remove redundant and incorrect initialization from *_iov_init() David Gibson
2023-01-06 0:43 ` [PATCH v3 12/18] tcp: Consolidate calculation of total frame size David Gibson
2023-01-06 0:43 ` [PATCH v3 13/18] tap: Add "tap headers" abstraction David Gibson
2023-01-06 0:43 ` [PATCH v3 14/18] tcp: Use abstracted tap header David Gibson
2023-01-06 0:43 ` [PATCH v3 15/18] tap: Use different io vector bases depending on tap type David Gibson
2023-01-06 0:43 ` [PATCH v3 16/18] udp: Use abstracted tap header David Gibson
2023-01-06 0:43 ` [PATCH v3 17/18] tap: Improve handling of partial frame sends David Gibson
2023-01-06 0:43 ` [PATCH v3 18/18] udp: Use tap_send_frames() David Gibson
2023-01-24 21:20 ` [PATCH v3 00/18] RFC: Unify and simplify tap send path Stefano Brivio
2023-01-25 3:13 ` David Gibson
2023-01-25 23:21 ` Stefano Brivio
2023-02-13 1:14 ` Stefano Brivio [this message]
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