From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Juergen Gross <jgross@suse.com>, <xen-devel@lists.xenproject.org>
Cc: Anthony PERARD <anthony.perard@citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>, Wei Liu <wl@xen.org>
Subject: Re: [Xen-devel] [PATCH] tools/libxl: make default of max event channels dependant on vcpus
Date: Thu, 26 Mar 2020 12:36:32 +0000 [thread overview]
Message-ID: <5a260627-c362-9fda-df42-8478df0e99e6@citrix.com> (raw)
In-Reply-To: <20200326094557.13822-1-jgross@suse.com>
On 26/03/2020 09:45, Juergen Gross wrote:
> Today the maximum number of event channels for a guest is defaulting
> to 1023. For large guests with lots of vcpus this is not enough, as
> e.g. the Linux kernel uses 7 event channels per vcpu, limiting the
> guest to about 140 vcpus.
>
> Instead of requiring to specify the allowed number of event channels
> via the "event_channels" domain config option, make the default
> depend on the maximum number of vcpus of the guest.
>
> In order not to regress current configs use 1023 as the minimum
> default setting.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
:(
I suspect I regressed this by making it not actually dead code.
1023 is the 32bit EVT 2L ABI limit, but until I moved max_evtchn into
the createdomain hypercall, I'm pretty sure a limit never used to get set.
If this is the case, then unlimited should be the default.
~Andrew
next prev parent reply other threads:[~2020-03-26 12:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-26 9:45 [Xen-devel] [PATCH] tools/libxl: make default of max event channels dependant on vcpus Juergen Gross
2020-03-26 9:54 ` Jan Beulich
2020-03-26 10:00 ` Jürgen Groß
2020-03-26 10:05 ` Jan Beulich
2020-03-26 10:11 ` Jürgen Groß
2020-03-26 10:29 ` Jürgen Groß
2020-03-26 12:36 ` Andrew Cooper [this message]
2020-03-26 12:42 ` Jürgen Groß
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