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Message-ID: <1313453362.2731.61.camel@bwh-desktop>
Date: Tue, 16 Aug 2011 01:09:22 +0100
From: Ben Hutchings <bhutchings@...arflare.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org, Eli Cohen <eli@....mellanox.co.il>
Subject: [PATCH net-next 5/5] ethtool: Note common alternate exit condition
for interrupt coalescing
Many implementations ignore the value of max_frames and do not
treat usecs == 0 as special. Document this as deprecated.
Signed-off-by: Ben Hutchings <bhutchings@...arflare.com>
---
include/linux/ethtool.h | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 42378b3..3829712 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -173,6 +173,12 @@ struct ethtool_eeprom {
* would cause interrupts to never be generated. To disable
* coalescing, set usecs = 0 and max_frames = 1.
*
+ * Some implementations ignore the value of max_frames and use the
+ * condition:
+ * time_since_first_completion >= usecs
+ * This is deprecated. Drivers for hardware that does not support
+ * counting completions should validate that max_frames == !rx_usecs.
+ *
* Adaptive RX/TX coalescing is an algorithm implemented by some
* drivers to improve latency under low packet rates and improve
* throughput under high packet rates. Some drivers only implement
--
1.7.4.4
--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
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