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Revision 6065fd0d179b96ddc488c76542349bcb148a95fd authored by Yuchung Cheng on 07 December 2017, 19:33:33 UTC, committed by David S. Miller on 08 December 2017, 19:14:11 UTC 
tcp: evaluate packet losses upon RTT change
 
RACK skips an ACK unless it advances the most recently delivered
TX timestamp (rack.mstamp). Since RACK also uses the most recent
RTT to decide if a packet is lost, RACK should still run the
loss detection whenever the most recent RTT changes. For example,
an ACK that does not advance the timestamp but triggers the cwnd
undo due to reordering, would then use the most recent (higher)
RTT measurement to detect further losses.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 428aec5
Raw File
parameters.txt 
Module Parameters in fmc.ko
***************************

The core driver receives two module parameters, meant to help debugging
client modules. Both parameters can be modified by writing to
/sys/module/fmc/parameters/, because they are used when client drivers
are devices are registered, not when fmc.ko is loaded.

`dump_eeprom='
     If not zero, the parameter asks the bus controller to dump the
     EEPROM of any device that is registered, using printk.

`dump_sdb='
     If not zero, the parameter prints the SDB tree of every FPGA it is
     loaded by fmc_reprogram(). If greater than one, it asks to dump
     the binary content of SDB records.  This currently only dumps the
     top-level SDB array, though.


EEPROM dumping avoids repeating lines, since most of the contents is
usually empty and all bits are one or zero. This is an example of the
output:

        [ 6625.850480] spec 0000:02:00.0: FPGA programming successful
        [ 6626.139949] spec 0000:02:00.0: Manufacturer: CERN
        [ 6626.144666] spec 0000:02:00.0: Product name: FmcDelay1ns4cha
        [ 6626.150370] FMC: mezzanine 0: 0000:02:00.0 on SPEC
        [ 6626.155179] FMC: dumping eeprom 0x2000 (8192) bytes
        [ 6626.160087] 0000: 01 00 00 01  00 0b 00 f3  01 0a 00 a5  85 87 c4 43
        [ 6626.167069] 0010: 45 52 4e cf  46 6d 63 44  65 6c 61 79  31 6e 73 34
        [ 6626.174019] 0020: 63 68 61 c7  70 72 6f 74  6f 2d 30 cc  45 44 41 2d
        [ 6626.180975] 0030: 30 32 32 36  37 2d 56 33  da 32 30 31  32 2d 31 31
        [...]
        [ 6626.371366] 0200: 66 64 65 6c  61 79 0a 00  00 00 00 00  00 00 00 00
        [ 6626.378359] 0210: 00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00
        [ 6626.385361] [...]
        [ 6626.387308] 1800: 70 6c 61 63  65 68 6f 6c  64 65 72 ff  ff ff ff ff
        [ 6626.394259] 1810: ff ff ff ff  ff ff ff ff  ff ff ff ff  ff ff ff ff
        [ 6626.401250] [...]

The dump of SDB looks like the following; the example shows the simple
golden gateware for the SPEC card, removing the leading timestamps to
fit the page:

        spec 0000:02:00.0: SDB: 00000651:e6a542c9 WB4-Crossbar-GSI
        spec 0000:02:00.0: SDB: 0000ce42:ff07fc47 WR-Periph-Syscon (00000000-000000ff)
        FMC: mezzanine 0: 0000:02:00.0 on SPEC
        FMC: poor dump of sdb first level:
        0000: 53 44 42 2d  00 02 01 00  00 00 00 00  00 00 00 00
        0010: 00 00 00 00  00 00 01 ff  00 00 00 00  00 00 06 51
        0020: e6 a5 42 c9  00 00 00 02  20 12 05 11  57 42 34 2d
        0030: 43 72 6f 73  73 62 61 72  2d 47 53 49  20 20 20 00
        0040: 00 00 01 01  00 00 00 07  00 00 00 00  00 00 00 00
        0050: 00 00 00 00  00 00 00 ff  00 00 00 00  00 00 ce 42
        0060: ff 07 fc 47  00 00 00 01  20 12 03 05  57 52 2d 50
        0070: 65 72 69 70  68 2d 53 79  73 63 6f 6e  20 20 20 01
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