Patchwork [RFC] Two ideas to optimize updating irq routing table

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Submitter Christian Borntraeger
Date March 26, 2014, 11:14 a.m.
Message ID <5332B69A.6060102@de.ibm.com>
Download mbox | patch
Permalink /patch/333830/
State New
Headers show

Comments

Christian Borntraeger - March 26, 2014, 11:14 a.m.
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


make the problem go away?

Patch

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