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authorJuergen Gross <jgross@suse.com>2021-02-19 16:40:28 +0100
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2021-02-23 10:07:11 -0600
commit06f45fe96fcd81531b0bcb2a6115da563ae6dbd6 (patch)
treee0004c9548d4612288b71f5fd541eab54fc63ead /Documentation
parent7c70f3a7488d2fa62d32849d138bf2b8420fe788 (diff)
xen/events: add per-xenbus device event statistics and settings
Add syfs nodes for each xenbus device showing event statistics (number of events and spurious events, number of associated event channels) and for setting a spurious event threshold in case a frontend is sending too many events without being rogue on purpose. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20210219154030.10892-7-jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'Documentation')
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+What: /sys/devices/*/xenbus/event_channels
+Date: February 2021
+Contact: Xen Developers mailing list <xen-devel@lists.xenproject.org>
+Description:
+ Number of Xen event channels associated with a kernel based
+ paravirtualized device frontend or backend.
+
+What: /sys/devices/*/xenbus/events
+Date: February 2021
+Contact: Xen Developers mailing list <xen-devel@lists.xenproject.org>
+Description:
+ Total number of Xen events received for a Xen pv device
+ frontend or backend.
+
+What: /sys/devices/*/xenbus/jiffies_eoi_delayed
+Date: February 2021
+Contact: Xen Developers mailing list <xen-devel@lists.xenproject.org>
+Description:
+ Summed up time in jiffies the EOI of an interrupt for a Xen
+ pv device has been delayed in order to avoid stalls due to
+ event storms. This value rising is a first sign for a rogue
+ other end of the pv device.
+
+What: /sys/devices/*/xenbus/spurious_events
+Date: February 2021
+Contact: Xen Developers mailing list <xen-devel@lists.xenproject.org>
+Description:
+ Number of events received for a Xen pv device which did not
+ require any action. Too many spurious events in a row will
+ trigger delayed EOI processing.
+
+What: /sys/devices/*/xenbus/spurious_threshold
+Date: February 2021
+Contact: Xen Developers mailing list <xen-devel@lists.xenproject.org>
+Description:
+ Controls the tolerated number of subsequent spurious events
+ before delayed EOI processing is triggered for a Xen pv
+ device. Default is 1. This can be modified in case the other
+ end of the pv device is issuing spurious events on a regular
+ basis and is known not to be malicious on purpose. Raising
+ the value for such cases can improve pv device performance.