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Date:      Tue, 22 Jan 2008 21:24:50 +0100
From:      Kris Kennaway <kris@FreeBSD.org>
To:        Stefan Lambrev <stefan.lambrev@moneybookers.com>
Cc:        =?UTF-8?B?RGFnLUVybGluZyBTbcO4cmdyYXY=?= <des@des.no>, freebsd-hackers@FreeBSD.org
Subject:   Re: gettimeofday() in hping
Message-ID:  <47965112.5020009@FreeBSD.org>
In-Reply-To: <47965072.7030700@moneybookers.com>
References:  <4795CC13.7080601@moneybookers.com>	<868x2i3v8d.fsf@ds4.des.no>	<864pd63v2h.fsf@ds4.des.no>	<4795FE54.9090606@moneybookers.com>	<86lk6i0vzk.fsf@ds4.des.no>	<479605E2.6070709@moneybookers.com>	<479621BE.2060907@FreeBSD.org> <4796357B.9020508@moneybookers.com> <47963911.4000002@FreeBSD.org> <47965072.7030700@moneybookers.com>

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Stefan Lambrev wrote:
> 
> Kris Kennaway wrote:
>> Stefan Lambrev wrote:
>>
>>>> You should use hwpmc to verify where the application is really 
>>>> spending time, since gettimeofday doesn't seem to account for it all.
>>> pmc: Unknown Intel CPU.
>>> module_register_init: MOD_LOAD (hwpmc, 0xffffffff8029906d, 
>>> 0xffffffff8054c500) error 78
>>
>> OK, this is the famous problem with modern CPUs that jkoshy has 
>> declined to work around :(  There are patches for this in perforce, see
>>
>> http://perforce.freebsd.org/changeView.cgi?CH=126189
> cc -c -O2 -frename-registers -pipe -fno-strict-aliasing -march=nocona 
> -std=c99 -g -Wall -Wredundant-decls -Wnested-externs 
> -Wstrict-prototypes  -Wmissing-prototypes -Wpointer-arith -Winline 
> -Wcast-qual  -Wundef -Wno-pointer-sign -fformat-extensions -nostdinc  
> -I. -I/usr/src/sys -I/usr/src/sys/contrib/altq -D_KERNEL 
> -DHAVE_KERNEL_OPTION_HEADERS -include opt_global.h -fno-common 
> -finline-limit=8000 --param inline-unit-growth=100 --param 
> large-function-growth=1000  -mcmodel=kernel -mno-red-zone  -mfpmath=387 
> -mno-sse -mno-sse2 -mno-mmx -mno-3dnow  -msoft-float 
> -fno-asynchronous-unwind-tables -ffreestanding -Werror  vers.c
> linking kernel.debug
> hwpmc_x86.o(.text+0x1a5): In function `pmc_md_initialize':
> /usr/src/sys/dev/hwpmc/hwpmc_x86.c:144: undefined reference to 
> `pmc_initialize_p6'
> 
> Any chance you have patches against RELENG_7_0 ? :)

They should apply, but maybe you will also need other patches from that 
branch.

>>> What was the other way to do this profiling?
>>
>> No other that I have found to be useful.
>>
>>> Can ktrace help?
>>
>> Not really, it only tells you what syscalls were made.
> But it can also display relative timestamps (time since previous entry).
> Can't this be useful?

Not really, it doesn't give enough of a cross-section into what your 
machine is spending its time doing.

Kris



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