From: Christian Borntraeger <borntraeger@de.ibm.com>
To: "Gonglei (Arei)" <arei.gonglei@huawei.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Cc: "Herongguang (Stephen)" <herongguang.he@huawei.com>,
"Huangweidong (C)" <weidong.huang@huawei.com>,
"avi.kivity@gmail.com" <avi.kivity@gmail.com>,
"gleb@redhat.com" <gleb@redhat.com>,
"mst@redhat.com" <mst@redhat.com>
Subject: Re: [Qemu-devel] [RFC]Two ideas to optimize updating irq routing table
Date: Wed, 26 Mar 2014 12:14:34 +0100 [thread overview]
Message-ID: <5332B69A.6060102@de.ibm.com> (raw)
In-Reply-To: <33183CC9F5247A488A2544077AF19020815DAEBA@SZXEMA503-MBS.china.huawei.com>
On 26/03/14 09:22, Gonglei (Arei) wrote:
> Without patches, ping time can jump from 0.3ms to 2ms-30ms. With synchronize_srcu
> patch, ping time is worse. With synchronize_srcu_expedited patch, ping time is
> overall good, though sometimes ping time jump to 1ms-3ms.
Just to understand whats going on, does something like
diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c
index 3318d82..432c2a2 100644
--- a/kernel/rcu/srcu.c
+++ b/kernel/rcu/srcu.c
@@ -331,7 +331,7 @@ EXPORT_SYMBOL_GPL(__srcu_read_unlock);
*/
#define SRCU_RETRY_CHECK_DELAY 5
#define SYNCHRONIZE_SRCU_TRYCOUNT 2
-#define SYNCHRONIZE_SRCU_EXP_TRYCOUNT 12
+#define SYNCHRONIZE_SRCU_EXP_TRYCOUNT 50
/*
* @@@ Wait until all pre-existing readers complete. Such readers
make the problem go away?
next prev parent reply other threads:[~2014-03-26 11:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-25 3:19 [Qemu-devel] [RFC]Two ideas to optimize updating irq routing table Gonglei (Arei)
2014-03-25 12:37 ` Paolo Bonzini
2014-03-26 8:16 ` Christian Borntraeger
2014-03-26 8:39 ` Gonglei (Arei)
2014-03-26 8:22 ` Gonglei (Arei)
2014-03-26 9:37 ` Paolo Bonzini
2014-03-26 11:14 ` Christian Borntraeger [this message]
2014-03-26 11:45 ` Michael S. Tsirkin
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