Searched hist:a606f432 (Results 1 – 2 of 2) sorted by relevance
/openbmc/linux/drivers/net/ethernet/sfc/ |
H A D | nic.c | a606f432 Mon May 23 06:18:45 CDT 2011 Steve Hodgson <shodgson@solarflare.com> sfc: Disable flow control during flushes
The TX DMA engine issues upstream read requests when there is room in the TX FIFO for the completion. However, the fetches for the rest of the packet might be delayed by any back pressure. Since a flush must wait for an EOP, the entire flush may be delayed by back pressure.
Mitigate this by disabling flow control before the flushes are started. Since PF and VF flushes run in parallel introduce fc_disable, a reference count of the number of flushes outstanding.
The same principle could be applied to Falcon, but that would bring with it its own testing.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> a606f432 Mon May 23 06:18:45 CDT 2011 Steve Hodgson <shodgson@solarflare.com> sfc: Disable flow control during flushes The TX DMA engine issues upstream read requests when there is room in the TX FIFO for the completion. However, the fetches for the rest of the packet might be delayed by any back pressure. Since a flush must wait for an EOP, the entire flush may be delayed by back pressure. Mitigate this by disabling flow control before the flushes are started. Since PF and VF flushes run in parallel introduce fc_disable, a reference count of the number of flushes outstanding. The same principle could be applied to Falcon, but that would bring with it its own testing. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
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H A D | net_driver.h | a606f432 Mon May 23 06:18:45 CDT 2011 Steve Hodgson <shodgson@solarflare.com> sfc: Disable flow control during flushes
The TX DMA engine issues upstream read requests when there is room in the TX FIFO for the completion. However, the fetches for the rest of the packet might be delayed by any back pressure. Since a flush must wait for an EOP, the entire flush may be delayed by back pressure.
Mitigate this by disabling flow control before the flushes are started. Since PF and VF flushes run in parallel introduce fc_disable, a reference count of the number of flushes outstanding.
The same principle could be applied to Falcon, but that would bring with it its own testing.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> a606f432 Mon May 23 06:18:45 CDT 2011 Steve Hodgson <shodgson@solarflare.com> sfc: Disable flow control during flushes The TX DMA engine issues upstream read requests when there is room in the TX FIFO for the completion. However, the fetches for the rest of the packet might be delayed by any back pressure. Since a flush must wait for an EOP, the entire flush may be delayed by back pressure. Mitigate this by disabling flow control before the flushes are started. Since PF and VF flushes run in parallel introduce fc_disable, a reference count of the number of flushes outstanding. The same principle could be applied to Falcon, but that would bring with it its own testing. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
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