* "tm->when" at /proc/net/tcp shows some negative numbers.
@ 2011-07-11 16:47 Andreas O
2011-07-11 17:28 ` Eric Dumazet
0 siblings, 1 reply; 2+ messages in thread
From: Andreas O @ 2011-07-11 16:47 UTC (permalink / raw)
To: netdev
Dear devnet list,
I am doing some performance improvements on linux-2.6.33.15 with
real-time support. When my tests fails I observe that "tm->when" at
/proc/net/tcp shows
some negative numbers. That negative number is the difference of
"timer_expires - jeffies" and in this case timer_expires is smaller
than jiffies.
Does this negative number indicates a bug in the stack?
from /proc/net/tcp
sl local_address rem_address st tx_queue rx_queue tr tm->when
retrnsmt uid timeout inode
0: 0100007F:09A4 00000000:0000 0A 00000000:00000000 00:00000000
00000000 499 0 11905 1 ffff88057b9df9c0 300 0 0 2 -1
1: 00000000:1BC7 00000000:0000 0A 00000000:00000000 00:00000000
00000000 499 0 14746 1 ffff880579bfac80 300 0 0 2 -1
2: 0100007F:00C7 00000000:0000 0A 00000000:00000000 00:00000000
00000000 0 0 11734 1 ffff88097a7980c0 300 0 0 2 -1
3: 00000000:078F 00000000:0000 0A 00000000:00000000 00:00000000
00000000 499 0 14733 1 ffff880974e9acc0 300 0 0 2 -1
4: 00000000:2710 00000000:0000 0A 00000000:00000000 00:00000000
00000000 499 0 14748 1 ffff88097385e740 300 0 0 2 -1
5: 00000000:0050 00000000:0000 0A 00000000:00000000 02:0000000E
00000000 499 0 14732 2 ffff88097933d980 300 0 0 2 -1
6: 14041AAC:0050 FE081AAC:93FD 03 00000000:00000000
01:FFFFFFFFFFFFFFE2 00000000 499 0 0 2 ffff8804dc549dc0
7: 14041AAC:0050 FA081AAC:B0E0 03 00000000:00000000
01:FFFFFFFFFFFFFFE2 00000000 499 0 0 2 ffff880524d79e40
8: 14041AAC:0050 F2011AAC:E53F 03 00000000:00000000
01:FFFFFFFFFFFFFFE4 00000000 499 0 0 2 ffff880524d7ccc0
9: 14041AAC:0050 F2011AAC:C73F 03 00000000:00000000
01:FFFFFFFFFFFFFFE5 00000000 499 0 0 2 ffff880524d5ba40
10: 14041AAC:0050 FB011AAC:D89A 03 00000000:00000000
01:FFFFFFFFFFFFFFE1 00000000 499 0 0 2 ffff8804a9290b40
11: 14041AAC:0050 F2011AAC:C9CD 03 00000000:00000000
01:FFFFFFFFFFFFFFE4 00000000 499 0 0 2 ffff8804e6c9af40
12: 14041AAC:0050 FE081AAC:8EC9 03 00000000:00000000
01:FFFFFFFFFFFFFFE2 00000000 499 0 0 2 ffff8804dc59d940
13: 14041AAC:0050 FE081AAC:E7C0 03 00000000:00000000
01:FFFFFFFFFFFFFFE2 00000000 499 0 0 2 ffff8804dc798840
sl local_address rem_address st tx_queue rx_queue tr tm->when
retrnsmt uid timeout inode
0: 0100007F:09A4 00000000:0000 0A 00000000:00000000 00:00000000
00000000 499 0 11905 1 ffff88057b9df9c0 300 0 0 2 -1
1: 00000000:1BC7 00000000:0000 0A 00000000:00000000 00:00000000
00000000 499 0 14746 1 ffff880579bfac80 300 0 0 2 -1
2: 0100007F:00C7 00000000:0000 0A 00000000:00000000 00:00000000
00000000 0 0 11734 1 ffff88097a7980c0 300 0 0 2 -1
3: 00000000:078F 00000000:0000 0A 00000000:00000000 00:00000000
00000000 499 0 14733 1 ffff880974e9acc0 300 0 0 2 -1
4: 00000000:2710 00000000:0000 0A 00000000:00000000 00:00000000
00000000 499 0 14748 1 ffff88097385e740 300 0 0 2 -1
5: 00000000:0050 00000000:0000 0A 00000000:00000000 02:00000009
00000000 499 0 14732 2 ffff88097933d980 300 0 0 2 -1
6: 14041AAC:0050 FE081AAC:93FD 03 00000000:00000000
01:FFFFFFFFFFFFFFB5 00000000 499 0 0 2 ffff8804dc549dc0
7: 14041AAC:0050 FA081AAC:B0E0 03 00000000:00000000
01:FFFFFFFFFFFFFFB5 00000000 499 0 0 2 ffff880524d79e40
8: 14041AAC:0050 F2011AAC:E53F 03 00000000:00000000
01:FFFFFFFFFFFFFFB7 00000000 499 0 0 2 ffff880524d7ccc0
9: 14041AAC:0050 F2011AAC:C73F 03 00000000:00000000
01:FFFFFFFFFFFFFFB8 00000000 499 0 0 2 ffff880524d5ba40
10: 14041AAC:0050 FB011AAC:D89A 03 00000000:00000000
01:FFFFFFFFFFFFFFB4 00000000 499 0 0 2 ffff8804a9290b40
11: 14041AAC:0050 F2011AAC:C9CD 03 00000000:00000000
01:FFFFFFFFFFFFFFB7 00000000 499 0 0 2 ffff8804e6c9af40
12: 14041AAC:0050 FE081AAC:8EC9 03 00000000:00000000
01:FFFFFFFFFFFFFFB5 00000000 499 0 0 2 ffff8804dc59d940
13: 14041AAC:0050 F2081AAC:E7BF 03 00000000:00000000
01:FFFFFFFFFFFFFFB7 00000000 499 0 0 2 ffff8804ce339c40
Any ideas?
Kind regards
Andreas
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: "tm->when" at /proc/net/tcp shows some negative numbers.
2011-07-11 16:47 "tm->when" at /proc/net/tcp shows some negative numbers Andreas O
@ 2011-07-11 17:28 ` Eric Dumazet
0 siblings, 0 replies; 2+ messages in thread
From: Eric Dumazet @ 2011-07-11 17:28 UTC (permalink / raw)
To: Andreas O; +Cc: netdev
Le lundi 11 juillet 2011 à 17:47 +0100, Andreas O a écrit :
> Dear devnet list,
>
> I am doing some performance improvements on linux-2.6.33.15 with
> real-time support. When my tests fails I observe that "tm->when" at
> /proc/net/tcp shows
> some negative numbers. That negative number is the difference of
> "timer_expires - jeffies" and in this case timer_expires is smaller
> than jiffies.
> Does this negative number indicates a bug in the stack?
>
>
Not necessarly.
If the thread handling timers is delayed (because of other more urgent
RT things), the delay between timer is fired and handled could be long.
^ permalink raw reply [flat|nested] 2+ messages in thread
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