gettimeofday() in hping

[Kris Kennaway]

Ivan Voras wrote:
> On 23/01/2008, Stefan Lambrev <stefan.lambrev at moneybookers.com> wrote:
>> Greets,
>>
>> Now I have final results with Linux and FreeBSD on the same hardware
>> CPU: Intel(R) Xeon(R) CPU 3070  @ 2.66GHz - dual core
>> Lan: em0 at pci0:3:0:0: class=0x020000 card=0x10bc8086 chip=0x10bc8086
>> rev=0x06 hdr=0x00
>>     vendor     = 'Intel Corporation'
>>     device     = '82571EB Gigabit Ethernet Controller (Copper)'
>>     class      = network
>>     subclass   = ethernet
>>
>> FreeBSD releng_7_0 from today - amd64, sched_ule.
>>
>> ACPI-Fast - 6.187 MB/s
>> TSC - 9.455 MB/s
>> dummy - 9.577 MB/s
>>
>> Linux rambo2 2.6.22-14-generic #1 SMP Tue Dec 18 05:28:27 UTC 2007
>> x86_64 GNU/Linux - kubuntu
>>
>> TSC - 19.456 MB/s
>> acpi_pm - 15.394 MB/s
>> jiffies - 19.480 MB/s
>>
>> This is really not what I expected.
> 
> For once, it's something I expected :) I just hope it isn't one of
> those cases where Kris absolutely cannot reproduce it and arrives at
> numbers in favour of FreeBSD :)
> (just joking here, absolutely no ill feelings involved).

Harumph :)  The first step is that we need to understand where the 
application is spending its time.  Hopefully Stefan or someone else will 
  be able to test it under hwpmc.

> It would be helpful if you post exact command line arguments from all cases.
> 
>> The other thing that bothers me is, that under freebsd is quite easy to get:
>> [send_ip] sendto: No buffer space available
>> It happens almost always on my laptop just few seconds after I start
>> hping with timecounter=TSC
> 
> I'm not sure, but from what I understood of Robert Watson's
> explanation in the big ZFS thread on -current, maybe increasing
> kmem_size (exactly as for ZFS...) could help you with these buffers.

It is the socket buffer that is filling up.  Either the application is 
not increasing it to large enough size or the default maximum is too low 
(Linux may set a larger default).  Try increasing kern.ipc.maxsockbuf 
and confirming with the source and/or ktrace that it is doing the right 
setsockopt() call.

Kris