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From: Stefan Hajnoczi <stefanha@redhat.com>
To: Bernd Schubert <bschubert@ddn.com>
Cc: Brian Song <hibriansong@gmail.com>,
	"qemu-block@nongnu.org" <qemu-block@nongnu.org>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	"armbru@redhat.com" <armbru@redhat.com>,
	"fam@euphon.net" <fam@euphon.net>,
	"hreitz@redhat.com" <hreitz@redhat.com>,
	"kwolf@redhat.com" <kwolf@redhat.com>
Subject: Re: [PATCH RFC 1/1] block/export: FUSE-over-io_uring Support for QEMU FUSE Exports
Date: Mon, 21 Jul 2025 14:26:21 -0400	[thread overview]
Message-ID: <20250721182621.GA69677@fedora> (raw)
In-Reply-To: <e13f8119-7c60-4aa6-91b0-860ac0a462f5@ddn.com>

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On Mon, Jul 21, 2025 at 01:51:44PM +0000, Bernd Schubert wrote:
> I need test these flags again, might be worthful for qemu as well
> 
> 	/* These flags should help to increase performance, but actually
> 	 * make it a bit slower - reason should get investigated.
> 	 */
> 	if (0) {
> 		/* Has the main slow down effect */
> 		params.flags |= IORING_SETUP_SINGLE_ISSUER;
> 
> 		// params.flags |= IORING_SETUP_DEFER_TASKRUN;
> 		params.flags |= IORING_SETUP_TASKRUN_FLAG;
> 
> 		/* Second main effect to make it slower */
> 		params.flags |= IORING_SETUP_COOP_TASKRUN;
> 	}

Yes, they are interesting. Thanks for mentioning them!

An earlier attempt at enabling IORING_SETUP_SINGLE_ISSUER in QEMU (still
needs benchmarking):
https://lore.kernel.org/qemu-devel/174293621917.22751.11381319865102029969-0%40git.sr.ht/T/#t

Let's consider these flags as a separate patch series. I have a
benchmarking setup that can be used for measurement, so I'll take this
as a TODO item for myself to work on over the coming days.

Thanks,
Stefan

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  reply	other threads:[~2025-07-21 18:28 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-16 18:38 [PATCH RFC 0/1] block/export: FUSE-over-io_uring Support for QEMU FUSE Exports Brian Song
2025-07-16 18:38 ` [PATCH RFC 1/1] " Brian Song
2025-07-17  6:03   ` Markus Armbruster
2025-07-22 12:00     ` Brian Song
2025-07-21  0:53   ` Stefan Hajnoczi
2025-07-22 12:00     ` Brian Song
2025-07-22 15:17       ` Kevin Wolf
2025-07-22 14:06     ` Bernd Schubert
2025-07-22 15:43       ` Stefan Hajnoczi
2025-07-22 16:20         ` Bernd Schubert
2025-07-21 13:51   ` Bernd Schubert
2025-07-21 18:26     ` Stefan Hajnoczi [this message]
2025-07-22 12:00     ` Brian Song
2025-07-22 14:51       ` Stefan Hajnoczi
2025-07-24 20:36     ` Stefan Hajnoczi
2025-07-22 13:32   ` Kevin Wolf
2025-07-20 16:13 ` [PATCH RFC 0/1] " Stefan Hajnoczi
2025-07-22 12:00   ` Brian Song
2025-07-22 14:47     ` Stefan Hajnoczi

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