Re: 1. thread switching time? (Krassimir Slavchev)

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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
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From: owner-freebsd-performance@xxxxxxxxxxx
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Sent: Thursday, October 30, 2008 8:00 PM
To: freebsd-performance@xxxxxxxxxxx
Subject: freebsd-performance Digest, Vol 68, Issue 4

Message: 1
Date: Wed, 29 Oct 2008 17:28:36 +0200
From: Krassimir Slavchev <krassi@xxxxxxxxxxx>
Subject: thread switching time?
To: freebsd-performance@xxxxxxxxxxx
Message-ID: <49088124.9050809@xxxxxxxxxxx>
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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