From: Ben Hutchings Date: Mon, 15 Aug 2011 14:07:47 +0000 (+0000) Subject: ethtool: Correct description of 'max_coalesced_frames' fields X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=2d7c79390eccd743a643db3fa577f4837e7f2b85;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git 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 Signed-off-by: David S. Miller --- 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. *