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| author | Ben Hutchings <bhutchings@solarflare.com> | 2011-08-15 14:08:37 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-08-16 16:36:15 -0700 |
| commit | acf42a2a575777681fee45ed59d7140be38e9142 (patch) | |
| tree | 8a5fc2c1005d389fedd4816926ab42d07fe96fd3 /include/linux/ethtool.h | |
| parent | 2d7c79390eccd743a643db3fa577f4837e7f2b85 (diff) | |
| download | lwn-acf42a2a575777681fee45ed59d7140be38e9142.tar.gz lwn-acf42a2a575777681fee45ed59d7140be38e9142.zip | |
ethtool: Explicitly state the exit condition for interrupt coalescing
Also explicitly state how to disable interrupt coalescing.
Remove the now-redundant text from field descriptions.
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 | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index 18059ca41f09..42378b34ae8f 100644 --- a/include/linux/ethtool.h +++ b/include/linux/ethtool.h @@ -121,20 +121,18 @@ struct ethtool_eeprom { * struct ethtool_coalesce - coalescing parameters for IRQs and stats updates * @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. + * a packet arrives. * @rx_max_coalesced_frames: Maximum number of packets to receive - * before an RX interrupt. If 0, only @rx_coalesce_usecs is used. + * before an RX interrupt. * @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, * except that this value applies while an IRQ is being serviced * by the host. * @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. + * a packet is sent. * @tx_max_coalesced_frames: Maximum number of packets to be sent - * before a TX interrupt. If 0, only @tx_coalesce_usecs is - * used. + * before a TX interrupt. * @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, @@ -167,8 +165,13 @@ struct ethtool_eeprom { * @rate_sample_interval: How often to do adaptive coalescing packet rate * sampling, measured in seconds. Must not be zero. * - * It is illegal to set both usecs and max frames to zero as this - * would cause interrupts to never be generated. + * Each pair of (usecs, max_frames) fields specifies this exit + * condition for interrupt coalescing: + * (usecs > 0 && time_since_first_completion >= usecs) || + * (max_frames > 0 && completed_frames >= max_frames) + * It is illegal to set both usecs and max_frames to zero as this + * would cause interrupts to never be generated. To disable + * coalescing, set usecs = 0 and max_frames = 1. * * Adaptive RX/TX coalescing is an algorithm implemented by some * drivers to improve latency under low packet rates and improve |