diff options
author | Ben Hutchings | 2011-08-15 14:07:47 +0000 |
---|---|---|
committer | David S. Miller | 2011-08-16 16:36:14 -0700 |
commit | 2d7c79390eccd743a643db3fa577f4837e7f2b85 (patch) | |
tree | 9c13001aac43a3f3de9e9d60778968faf56a92b5 /include/linux/ethtool.h | |
parent | 725b361b29ba9fb72705a30743d288ee66055209 (diff) |
ethtool: Correct description of 'max_coalesced_frames' fields
The current descriptions state that these fields specify 'How many
packets to delay ... after a packet ...' which implies that the
hardware should wait for (max_coalesced_frames + 1) completions before
generating an interrupt. It is also stated that setting both this
field and the corresponding 'coalesce_usecs' field to 0 is invalid.
Together, this implies that the hardware must always be configured
to delay a completion IRQ for at least 1 usec or 1 more completion.
I believe that the addition of 1 is not intended, and David Miller
confirms that the original implementation (in tg3) does not do this.
Clarify the descriptions of these fields to avoid this interpretation.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/ethtool.h')
-rw-r--r-- | include/linux/ethtool.h | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index 71d45a199f96..18059ca41f09 100644 --- a/include/linux/ethtool.h +++ b/include/linux/ethtool.h @@ -122,8 +122,8 @@ struct ethtool_eeprom { * @cmd: ETHTOOL_{G,S}COALESCE * @rx_coalesce_usecs: How many usecs to delay an RX interrupt after * a packet arrives. If 0, only @rx_max_coalesced_frames is used. - * @rx_max_coalesced_frames: How many packets to delay an RX interrupt - * after a packet arrives. If 0, only @rx_coalesce_usecs is used. + * @rx_max_coalesced_frames: Maximum number of packets to receive + * before an RX interrupt. If 0, only @rx_coalesce_usecs is used. * @rx_coalesce_usecs_irq: Same as @rx_coalesce_usecs, except that * this value applies while an IRQ is being serviced by the host. * @rx_max_coalesced_frames_irq: Same as @rx_max_coalesced_frames, @@ -132,9 +132,9 @@ struct ethtool_eeprom { * @tx_coalesce_usecs: How many usecs to delay a TX interrupt after * a packet is sent. If 0, only @tx_max_coalesced_frames * is used. - * @tx_max_coalesced_frames: How many packets to delay a TX interrupt - * after a packet is sent. If 0, only @tx_coalesce_usecs is - * used. + * @tx_max_coalesced_frames: Maximum number of packets to be sent + * before a TX interrupt. If 0, only @tx_coalesce_usecs is + * used. * @tx_coalesce_usecs_irq: Same as @tx_coalesce_usecs, except that * this value applies while an IRQ is being serviced by the host. * @tx_max_coalesced_frames_irq: Same as @tx_max_coalesced_frames, @@ -149,21 +149,21 @@ struct ethtool_eeprom { * @pkt_rate_low: Threshold for low packet rate (packets per second). * @rx_coalesce_usecs_low: How many usecs to delay an RX interrupt after * a packet arrives, when the packet rate is below @pkt_rate_low. - * @rx_max_coalesced_frames_low: How many packets to delay an RX interrupt - * after a packet arrives, when the packet rate is below @pkt_rate_low. + * @rx_max_coalesced_frames_low: Maximum number of packets to be received + * before an RX interrupt, when the packet rate is below @pkt_rate_low. * @tx_coalesce_usecs_low: How many usecs to delay a TX interrupt after * a packet is sent, when the packet rate is below @pkt_rate_low. - * @tx_max_coalesced_frames_low: How many packets to delay a TX interrupt - * after a packet is sent, when the packet rate is below @pkt_rate_low. + * @tx_max_coalesced_frames_low: Maximum nuumber of packets to be sent before + * a TX interrupt, when the packet rate is below @pkt_rate_low. * @pkt_rate_high: Threshold for high packet rate (packets per second). * @rx_coalesce_usecs_high: How many usecs to delay an RX interrupt after * a packet arrives, when the packet rate is above @pkt_rate_high. - * @rx_max_coalesced_frames_high: How many packets to delay an RX interrupt - * after a packet arrives, when the packet rate is above @pkt_rate_high. + * @rx_max_coalesced_frames_high: Maximum number of packets to be received + * before an RX interrupt, when the packet rate is above @pkt_rate_high. * @tx_coalesce_usecs_high: How many usecs to delay a TX interrupt after * a packet is sent, when the packet rate is above @pkt_rate_high. - * @tx_max_coalesced_frames_high: How many packets to delay a TX interrupt - * after a packet is sent, when the packet rate is above @pkt_rate_high. + * @tx_max_coalesced_frames_high: Maximum number of packets to be sent before + * a TX interrupt, when the packet rate is above @pkt_rate_high. * @rate_sample_interval: How often to do adaptive coalescing packet rate * sampling, measured in seconds. Must not be zero. * |