From: Dominique Martinet <asmadeus@codewreck.org>
To: Christian Schoenebeck <linux_oss@crudebyte.com>
Cc: v9fs-developer@lists.sourceforge.net, netdev@vger.kernel.org,
Eric Van Hensbergen <ericvh@gmail.com>,
Latchesar Ionkov <lucho@ionkov.net>, Greg Kurz <groug@kaod.org>,
Vivek Goyal <vgoyal@redhat.com>,
Nikolay Kichukov <nikolay@oldum.net>
Subject: Re: [PATCH v4 12/12] net/9p: allocate appropriate reduced message buffers
Date: Sat, 2 Apr 2022 23:05:36 +0900 [thread overview]
Message-ID: <YkhYMFf63qnEhDd0@codewreck.org> (raw)
In-Reply-To: <8c305df4646b65218978fc6474aa0f5f29b216a0.1640870037.git.linux_oss@crudebyte.com>
Christian Schoenebeck wrote on Thu, Dec 30, 2021 at 02:23:18PM +0100:
> So far 'msize' was simply used for all 9p message types, which is far
> too much and slowed down performance tremendously with large values
> for user configurable 'msize' option.
>
> Let's stop this waste by using the new p9_msg_buf_size() function for
> allocating more appropriate, smaller buffers according to what is
> actually sent over the wire.
By the way, thinking of protocols earlier made me realize this won't
work on RDMA transport...
unlike virtio/tcp/xen, RDMA doesn't "mailbox" messages: there's a pool
of posted buffers, and once a message has been received it looks for the
header in the received message and associates it with the matching
request, but there's no guarantee a small message will use a small
buffer...
This is also going to need some thought, perhaps just copying small
buffers and recycling the buffer if a large one was used? but there
might be a window with no buffer available and I'm not sure what'd
happen, and don't have any RDMA hardware available to test this right
now so this will be fun.
I'm not shooting this down (it's definitely interesting), but we might
need to make it optional until someone with RDMA hardware can validate a
solution.
--
Dominique
next prev parent reply other threads:[~2022-04-02 14:06 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-30 13:23 [PATCH v4 00/12] remove msize limit in virtio transport Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 12/12] net/9p: allocate appropriate reduced message buffers Christian Schoenebeck
2022-04-02 14:05 ` Dominique Martinet [this message]
2022-04-03 11:29 ` Christian Schoenebeck
2022-04-03 12:37 ` Dominique Martinet
2022-04-03 14:00 ` Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 08/12] net/9p: limit 'msize' to KMALLOC_MAX_SIZE for all transports Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 04/12] 9p/trans_virtio: introduce struct virtqueue_sg Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 01/12] net/9p: show error message if user 'msize' cannot be satisfied Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 10/12] 9p: add P9_ERRMAX for 9p2000 and 9p2000.u Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 11/12] net/9p: add p9_msg_buf_size() Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 06/12] 9p/trans_virtio: support larger msize values Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 02/12] 9p/trans_virtio: separate allocation of scatter gather list Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 09/12] net/9p: split message size argument into 't_size' and 'r_size' pair Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 07/12] 9p/trans_virtio: resize sg lists to whatever is possible Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 05/12] net/9p: add trans_maxsize to struct p9_client Christian Schoenebeck
2021-12-30 13:23 ` [PATCH v4 03/12] 9p/trans_virtio: turn amount of sg lists into runtime info Christian Schoenebeck
2022-01-20 22:43 ` [PATCH v4 00/12] remove msize limit in virtio transport Nikolay Kichukov
2022-01-22 13:34 ` Christian Schoenebeck
2022-01-24 10:21 ` Nikolay Kichukov
2022-01-24 11:07 ` Dominique Martinet
2022-01-24 11:57 ` Christian Schoenebeck
2022-01-24 12:56 ` Dominique Martinet
2022-01-24 13:55 ` Christian Schoenebeck
2022-01-25 8:45 ` Nikolay Kichukov
2022-05-24 8:10 ` Nikolay Kichukov
2022-05-24 11:29 ` Christian Schoenebeck
2022-07-07 14:30 ` Christian Schoenebeck
[not found] ` <CAFkjPT=GAoViYd0E7CZQDq3ZjhmYT0DsBytfZXnE10JL0P8O-Q@mail.gmail.com>
2022-07-08 1:15 ` Dominique Martinet
[not found] ` <CAFkjPTngeFh=0mPVW-Yf1Sxkxp_HDNUeANndoYN3-eU9_rGLuQ@mail.gmail.com>
2022-07-08 11:18 ` Christian Schoenebeck
2022-07-08 11:40 ` Dominique Martinet
2022-07-08 13:00 ` Christian Schoenebeck
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