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Date:      Fri, 31 Oct 2008 09:32:07 +0200
From:      Krassimir Slavchev <krassi@bulinfo.net>
To:        Sam Xia <xiazhongqi@huawei.com>
Cc:        freebsd-performance@freebsd.org
Subject:   Re: 1. thread switching time? (Krassimir Slavchev)
Message-ID:  <490AB477.2080001@bulinfo.net>
In-Reply-To: <000001c93b0c$6195e6b0$2f096f0a@china.huawei.com>
References:  <000001c93b0c$6195e6b0$2f096f0a@china.huawei.com>

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Hi,


Sam Xia wrote:
> hi krassi,
> 
>  what kind of hardware are you using?  Actually because of process/thread
> scheduling mechanism, timing granulariy is coarse in FreeBSD(more than 10
> ms)

dmesg:
...
CPU: Intel(R) Core(TM)2 CPU         E8400  @ 3.00GHz (3005.25-MHz
686-class CPU)
...
Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x408-0x40b on acpi0
acpi_hpet0: <High Precision Event Timer> iomem 0xfed00000-0xfed003ff on
acpi0
Timecounter "HPET" frequency 14318180 Hz quality 900
...

The hardware is fast enough!

Also, I am able to set HZ=100000 but the thread switching time is still
~1ms.


Best Regards

>  
> S.X
>> -----Original Message-----
>> From: owner-freebsd-performance@freebsd.org 
>> [mailto:owner-freebsd-performance@freebsd.org] On Behalf Of 
>> freebsd-performance-request@freebsd.org
>> Sent: Thursday, October 30, 2008 8:00 PM
>> To: freebsd-performance@freebsd.org
>> Subject: freebsd-performance Digest, Vol 68, Issue 4
> 
>> Message: 1
>> Date: Wed, 29 Oct 2008 17:28:36 +0200
>> From: Krassimir Slavchev <krassi@bulinfo.net>
>> Subject: thread switching time?
>> To: freebsd-performance@freebsd.org
>> Message-ID: <49088124.9050809@bulinfo.net>
>> Content-Type: text/plain; charset=ISO-8859-1
>>
> Hello All,
> 
> I am using FreeBSD 7 and would like to decrease the time of 
> switching between threads. This time seems to be 1ms and it 
> is impossible to make lower delays inside a thread, at least 
> using nanosleep().
> 
> Is it possible to decrease this time to 1us?
> 
> 
> Best Regards
>>
>>
**************************************************
>>

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