From: David Laight <David.Laight@ACULAB.COM>
To: 'Willy Tarreau' <w@1wt.eu>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: RE: Feedback on 4.9 performance after PTI fixes
Date: Mon, 8 Jan 2018 17:26:06 +0000 [thread overview]
Message-ID: <fdaddeb70a924e499fe9ee64c61fd9ed@AcuMS.aculab.com> (raw)
In-Reply-To: <20180107101856.GA9590@1wt.eu>
From: Willy Tarreau
> Sent: 07 January 2018 10:19
...
> The impact inside VMs is quite big but it's not where we usuall install
> processes sensitive to syscall performance. I could find an even higher
> impact on a packet generation program dropping from 2.5 Mpps to 600kpps
> in the VM after the fix, but it doesn't make much sense to do this in
> VMs so I don't really care.
Why not?
It will be related to the cost of sending (and probably receiving)
network traffic in a VM.
This is something that is done a lot.
Maybe not packet generation, but a UDP/IP benchmark inside a VM would
be sensible.
It may well be that moderate ethernet packet rates cause a massive
performance drop when the host kernel has PTI enabled.
David
next prev parent reply other threads:[~2018-01-08 17:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-07 10:18 Feedback on 4.9 performance after PTI fixes Willy Tarreau
2018-01-08 17:07 ` Yves-Alexis Perez
2018-01-08 17:21 ` Yves-Alexis Perez
2018-01-08 18:26 ` Willy Tarreau
2018-01-08 20:26 ` Yves-Alexis Perez
2018-01-08 20:39 ` Willy Tarreau
2018-01-08 22:45 ` Pavlos Parissis
2018-01-08 17:26 ` David Laight [this message]
2018-01-09 7:09 ` Willy Tarreau
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