On Mon, 04 Jun 2007 08:39:48 +0200
Thomas Gleixner [off-list ref] wrote:

On Sun, 2007-06-03 at 18:26 +0200, Maximilian Engelhardt wrote:

quoted

quoted

Is there any other strange behavior of the high res enabled kernel than
the b44 problem ?

I didn't notice anything in the past (as I wrote). But today I did some tests 
for an updated version of the p54 mac80211 wlan driver and I noticed exactly 
the same problem:

when booting with highres=off everything is fine.
But when I boot an highres enabled kernel and I do the iperf-test with the p54 
driver, my systems becomes unresponsive during the test. It seems to be 
exactly the same problem I have with the b44 driver.
So this might not be a bug in the b44 code but a bug somewhere in the linux 
networking code.

I did the test with an 2.6.22-rc3-git4 kernel and the p54 driver built 
external as module. 

Can you look at iperf to figure out, whether it does some weird timer
stuff (high frequency interval timer or such) ? Either check the code or
strace it.

	tglx

It is the receiver doing a tight loop doing gettimeofday/recv calls.


sendto(-1227715616, 0xc, 3085438964, 0, {...}, 3067249832) = 0
gettimeofday({1180973726, 981615}, NULL) = 0
gettimeofday({1180973726, 981751}, NULL) = 0
futex(0x8055c64, 0x5 /* FUTEX_??? */, 1) = 1
futex(0x8055c90, FUTEX_WAKE, 1) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 982754}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 983790}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 984355}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 984706}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 985111}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 985499}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 986088}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 986436}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 986916}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 987397}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 987872}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 988440}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 988823}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 989314}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 990029}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 990890}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 991803}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 992616}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 993105}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 993585}, NULL) = 0
recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
gettimeofday({1180973726, 994014}, NULL) = 0
...

recv(4, "45678901234567890123456789012345"..., 8192, 0) = 1448
gettimeofday({1180973757, 172437}, NULL) = 0
recv(4, "23456789012345678901234567890123"..., 8192, 0) = 1448
gettimeofday({1180973757, 172576}, NULL) = 0
recv(4, "01234567890123456789012345678901"..., 8192, 0) = 1632
gettimeofday({1180973757, 172752}, NULL) = 0
recv(4, "", 8192, 0)                    = 0
gettimeofday({1180973757, 172797}, NULL) = 0
gettimeofday({1180973757, 172817}, NULL) = 0
nanosleep({0, 0}, NULL) = 0
nanosleep({0, 0}, NULL)                 = 0
close(4)                     = 0
futex(0x8055d04, 0x5 /* FUTEX_??? */, 1) = 1
futex(0x8055d30, FUTEX_WAKE, 1) = 0
_exit(0)

-- 
Stephen Hemminger [off-list ref]