From: David Vrabel <david.vrabel@citrix.com>
To: xen-devel@lists.xenproject.org
Cc: Keir Fraser <keir@xen.org>, Tim Deegan <tim@xen.org>,
David Vrabel <david.vrabel@citrix.com>,
Jan Beulich <jbeulich@suse.com>,
Ian Campbell <ian.campbell@citrix.com>
Subject: [PATCHv2 5/5] evtchn: pad struct evtchn to 64 bytes
Date: Mon, 15 Jun 2015 16:48:19 +0100 [thread overview]
Message-ID: <1434383299-21833-6-git-send-email-david.vrabel@citrix.com> (raw)
In-Reply-To: <1434383299-21833-1-git-send-email-david.vrabel@citrix.com>
The number of struct evtchn in a page must be a power of two. Under
some workloads performance is improved slightly by padding struct
evtchn to 64 bytes (a cache line), thus putting the per-channel locks
into their own cache line.
This does not decrease the number of struct evtchn's per-page.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
I'm not sure we actually want to do this. I think it would be better
to pack the struct evtchn and use vmap to turn the pages into a linear
array for quicker lookup.
---
xen/include/xen/sched.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 44ea92d..a0ff9d2 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -129,7 +129,7 @@ struct evtchn
#endif
} ssid;
#endif
-};
+} __attribute__((aligned(64)));
int evtchn_init(struct domain *d); /* from domain_create */
void evtchn_destroy(struct domain *d); /* from domain_kill */
--
1.7.10.4
next prev parent reply other threads:[~2015-06-15 16:38 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-15 15:48 [PATCHv2 0/5] evtchn: Improve scalebility David Vrabel
2015-06-15 15:48 ` [PATCHv2 1/5] evtchn: factor out freeing an event channel David Vrabel
2015-06-15 15:48 ` [PATCHv2 2/5] evtchn: simplify port_is_valid() David Vrabel
2015-06-15 15:57 ` Ian Campbell
2015-06-15 15:59 ` David Vrabel
2015-06-15 16:09 ` Ian Campbell
2015-06-15 15:48 ` [PATCHv2 3/5] evtchn: use a per-event channel lock for sending events David Vrabel
2015-06-16 9:18 ` Jan Beulich
2015-06-16 9:34 ` David Vrabel
2015-06-16 9:51 ` Jan Beulich
2015-06-16 9:57 ` David Vrabel
2015-06-16 15:19 ` David Vrabel
2015-06-16 15:58 ` David Vrabel
2015-06-16 16:19 ` Jan Beulich
2015-06-16 16:39 ` David Vrabel
2015-06-17 7:05 ` Jan Beulich
2015-06-16 16:06 ` Jan Beulich
2015-06-15 15:48 ` [PATCHv2 4/5] evtchn: remove the locking when unmasking an event channel David Vrabel
2015-06-16 9:19 ` Jan Beulich
2015-06-16 9:40 ` David Vrabel
2015-06-15 15:48 ` David Vrabel [this message]
2015-06-16 9:22 ` [PATCHv2 5/5] evtchn: pad struct evtchn to 64 bytes Jan Beulich
2015-06-16 11:14 ` Julien Grall
2015-06-16 11:59 ` Jan Beulich
2015-06-16 12:57 ` Julien Grall
2015-06-16 13:13 ` David Vrabel
2015-06-16 13:27 ` Julien Grall
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