[opensuse-kernel] Suggestion set the default Timer frequency to 1000 HZ
While poking around in the kernel source I learned that openSUSE's default Timer frequency is set to 250 HZ. Which is good for server usage. Why not set the default Timer frequency to 1000 HZ which is better suited for desktop? -- Regards, Aniruddha Please adhere to the OpenSUSE_mailing_list_netiquette http://en.opensuse.org/OpenSUSE_mailing_list_netiquette -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
On Oct 14 2007 14:24, Aniruddha wrote:
While poking around in the kernel source I learned that openSUSE's default Timer frequency is set to 250 HZ. Which is good for server usage.
Why not set the default Timer frequency to 1000 HZ which is better suited for desktop?
Because not everyone runs a desktop. Use -rt. -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
On Sun, 2007-10-14 at 14:25 +0200, Jan Engelhardt wrote:
On Oct 14 2007 14:24, Aniruddha wrote:
While poking around in the kernel source I learned that openSUSE's default Timer frequency is set to 250 HZ. Which is good for server usage.
Why not set the default Timer frequency to 1000 HZ which is better suited for desktop?
Because not everyone runs a desktop. Use -rt.
openSUSE main focus appears to be the desktop not the server. Why focus on the desktop from the outside but cripple it's default inner workings? What is -rt? -- Regards, Aniruddha Please adhere to the OpenSUSE_mailing_list_netiquette http://en.opensuse.org/OpenSUSE_mailing_list_netiquette -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
On Oct 14 2007 14:45, Aniruddha wrote:
While poking around in the kernel source I learned that openSUSE's default Timer frequency is set to 250 HZ. Which is good for server usage.
Why not set the default Timer frequency to 1000 HZ which is better suited for desktop?
Because not everyone runs a desktop. Use -rt.
openSUSE main focus appears to be the desktop not the server.
Look a bit further, then. Lots of people don't need nor want SLES.
Why focus on the desktop from the outside but cripple it's default inner workings?
Read http://kerneltrap.org/node/5411 , nothing is crippled. 1000 is not magic.
What is -rt?
realtime kernel. I thought you could figure since this is a kernel-related list. -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
On Sun, 2007-10-14 at 14:52 +0200, Jan Engelhardt wrote:
realtime kernel. I thought you could figure since this is a kernel-related list.
There is no need to talk in a demeaning manner, please watch your tone. What is the exact difference between kernel-rt and the kernel-default package? -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
On Oct 14 2007 15:06, Aniruddha wrote:
On Sun, 2007-10-14 at 14:52 +0200, Jan Engelhardt wrote:
realtime kernel. I thought you could figure since this is a kernel-related list.
There is no need to talk in a demeaning manner, please watch your tone.
What is the exact difference between kernel-rt and the kernel-default package?
Technically speaking, the config options: http://rafb.net/p/ciyR0n64.html -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Jan Engelhardt wrote:
On Oct 14 2007 15:06, Aniruddha wrote:
On Sun, 2007-10-14 at 14:52 +0200, Jan Engelhardt wrote:
realtime kernel. I thought you could figure since this is a kernel-related list.
There is no need to talk in a demeaning manner, please watch your tone.
What is the exact difference between kernel-rt and the kernel-default package?
Technically speaking, the config options: http://rafb.net/p/ciyR0n64.html
While the config options do play a role, the bigger difference is an additional 1.6 MB patch[1] that gets applied to the -rt tree that changes the latency behaviors in a lot of areas. With a few exceptions, most spinlocks become sleeping locks. It targets low latency rather than overall throughput. Realtime simulations use it, so the behavior of the system is more predictable. I've also seen favorable reports from users doing audio/video work as well. In general, though, it's not really what you want for your default system. It's the only kernel we ship where the source tree differs between flavors. In the long term, we hope to eliminate that distinction, but there are too many parts of -rt that can't be built conditionally and we don't want to suck it all in for ever flavor. - -Jeff [1] http://www.kernel.org/pub/linux/kernel/projects/rt/ - Note: This patch is different than the one in the CVS repo since we have to port it to our kernel source. However, for demonstration purposes, it's sufficient. The changes were pretty minor. - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFHEkAALPWxlyuTD7IRAtrRAKCKBCYNH0L01ugSeH2r+zfa5nWKLACfXpJk ijgAXT+xf/Y0bGlDlc7jO4s= =ezbf -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
On Oct 14 2007 12:12, Jeff Mahoney wrote:
It's the only kernel we ship where the source tree differs between flavors.
Is that a problem? I do not think so, since I managed to create a kernel-rt-source without many changes to the specfile. (Largely the use of %macros I've been talking about and about, and a few naming changes). And all it takes to build rt KMPs is to make sure the rt-source is available in the build system (along with the rest of the gang, kernel-syms, kernel-source).
In the long term, we hope to eliminate that distinction, but there are too many parts of -rt that can't be built conditionally and we don't want to suck it all in for ever flavor. -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Jan Engelhardt wrote:
On Oct 14 2007 12:12, Jeff Mahoney wrote:
It's the only kernel we ship where the source tree differs between flavors.
Is that a problem? I do not think so, since I managed to create a kernel-rt-source without many changes to the specfile. (Largely the use of %macros I've been talking about and about, and a few naming changes). And all it takes to build rt KMPs is to make sure the rt-source is available in the build system (along with the rest of the gang, kernel-syms, kernel-source).
When it's only one case, it's not so bad. You've just described the problem. However, with older releases (in the 8.x days), we had a different kernel source tree for every architecture, which was a pain to manage. Maintaining a single source tree for all architectures and flavors has been a goal for the kernel teams for quite some time, and with this one recent exception, it's one we've been successful at obtaining. - -Jeff - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFHEkLGLPWxlyuTD7IRAmgpAKCnzSouAhR40jZFDQob/iak2USYSwCgiER7 pXO6332m7nP0KmjVq/e/HUE= =9qw8 -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Aniruddha wrote:
While poking around in the kernel source I learned that openSUSE's default Timer frequency is set to 250 HZ. Which is good for server usage.
Why not set the default Timer frequency to 1000 HZ which is better suited for desktop?
The cost/benefit just isn't worth it. A higher HZ value carries a cost with it: The system fires off the timer 4x as frequently, which means it's busy running the timer interrupt when it could be something else - like running your programs, or more importantly, idling the CPU. This can affect battery life in notebooks, which DO fall in the "desktop" category. That said, the 10.3 kernels on i386 machines are tickless. The timer interrupt is set up on an on-demand basis, so the HZ value really shouldn't matter. Tickless support hasn't been implemented for x86_64 yet, though. - -Jeff - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFHEkQFLPWxlyuTD7IRAlwDAKCpF/AQFyTKo6o+v7wAFl8Avmt2gQCeP68E PjG2/YhdwXYOBI+LJq61oNM= =ER5F -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
On Oct 14 2007 12:29, Jeff Mahoney wrote:
That said, the 10.3 kernels on i386 machines are tickless. The timer interrupt is set up on an on-demand basis, so the HZ value really shouldn't matter. Tickless support hasn't been implemented for x86_64 yet, though.
rt is tickless, even on x86_64. But I've gone with the following layout: -regular 100 Hz -default 300 Hz [http://lwn.net/Articles/208411/] -rt 1000 Hz -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Jan Engelhardt wrote:
On Oct 14 2007 12:29, Jeff Mahoney wrote:
That said, the 10.3 kernels on i386 machines are tickless. The timer interrupt is set up on an on-demand basis, so the HZ value really shouldn't matter. Tickless support hasn't been implemented for x86_64 yet, though.
rt is tickless, even on x86_64. But I've gone with the following layout: -regular 100 Hz -default 300 Hz [http://lwn.net/Articles/208411/] -rt 1000 Hz
Oh cool. I didn't realize that. The -rt kernel has been managed by a separate group. I suspect there a few patches lurking in there that would be nice to apply unconditionally. - -Jeff - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFHEkhKLPWxlyuTD7IRAhwwAJ4xCX+FMWzSa5af0JmihSsL3NuSdwCdF4fW v4PQCLP1MsfVbDnSSW9W+Ns= =mDEh -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
On Sun, 2007-10-14 at 18:40 +0200, Jan Engelhardt wrote:
On Oct 14 2007 12:29, Jeff Mahoney wrote:
That said, the 10.3 kernels on i386 machines are tickless. The timer interrupt is set up on an on-demand basis, so the HZ value really shouldn't matter. Tickless support hasn't been implemented for x86_64 yet, though.
rt is tickless, even on x86_64. But I've gone with the following layout: -regular 100 Hz -default 300 Hz [http://lwn.net/Articles/208411/] -rt 1000 Hz
Thanks for all the info and links :D in short the rt kernel has a default Timer frequency of 1000 HZ and other patches to improve performance right? -- Regards, Aniruddha Please adhere to the OpenSUSE_mailing_list_netiquette http://en.opensuse.org/OpenSUSE_mailing_list_netiquette -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
On Oct 14 2007 21:22, Aniruddha wrote:
Thanks for all the info and links :D in short the rt kernel has a default Timer frequency of 1000 HZ and other patches to improve performance right?
1000 Hz is not a performance improvement. -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org
participants (3)
-
Aniruddha -
Jan Engelhardt -
Jeff Mahoney