Difference between revisions of "Talk:Improving performance"

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== Watchdog section ==
This doesn't work:
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mkfs.xfs -l internal,lazy-count=1 size=128m -d agcount=2 /dev/sdxx
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--[[User:Jkd.luca|Jkd.luca]] 17:21, 4 October 2010 (EDT)
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I've added a '''watchdogs''' section.
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Tell me what do you think about? --[[User:NTia89|nTia89]] ([[User talk:NTia89|talk]]) 10:42, 29 December 2016 (UTC)
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:Is it really recommended to disable watchdog services? See [https://linux.die.net/man/8/watchdog watchdog(8)]. Even when running a 'simple' desktop, it needs to monitor a lot of things. Don't forget most MB use a watchdog service. How to know this is really safe? [[User:Francoism|Francoism]] ([[User talk:Francoism|talk]]) 10:52, 29 December 2016 (UTC)
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::1. I've never had a problem, see also: https://bbs.archlinux.org/viewtopic.php?id=163768 --[[User:NTia89|nTia89]] ([[User talk:NTia89|talk]]) 11:01, 29 December 2016 (UTC)
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::2. Your watchdog is related to the specific program ''watchdog'' (https://www.archlinux.org/packages/extra/x86_64/watchdog/), a standalone program, not installed by default, not dependency of other packages. --[[User:NTia89|nTia89]] ([[User talk:NTia89|talk]]) 11:05, 29 December 2016 (UTC)
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:::You are correct about the watchdog package, but it is just to give you an example of what a watchdog does. It also depends on the hardware and software that's in use. To give you an example, an USB device that causes issues, will be unable to recover if no watchdog is in use. It can also lead to unexpected reboots (a watchdog is able to perform recovery operations) and maybe even hardware damage (see temperature monitoring). The one in the kernel are linked with the CPU/MB it seems, think they are created for some reason. ;) [[User:Francoism|Francoism]] ([[User talk:Francoism|talk]]) 11:13, 29 December 2016 (UTC)
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::::No, I don't think so. Low-level hardware interrupt are handled by low-level software, the BIOS/EFI.
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::::For what watchdogs do, read the first and third link.
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::::I'm with you that "if it exists, there is a good reason, so...", but this doesn't mean everybody need it.
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::::PS: What I've written on the wiki is the sum/product of what I have understand/learn about kernel watchdog; an issue started time ago while for the first time I've read about "NMI_watchdog" in the dmesg; the links provided at the end of my edit are the sources from which I extrapolated those information; if you have other sources, share, I'm here to learn in primis.  --[[User:NTia89|nTia89]] ([[User talk:NTia89|talk]]) 14:54, 29 December 2016 (UTC)
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:::::[https://gist.github.com/lahwaacz/5bef7a353cd8cbe49164d2bf4efd47fa Here] is what I get from time to time after plugging someting into my only USB3 port. After that happens, I need to reboot to make it work again. It's definitely tied up to the hardware driver and I'm not really interested in finding out what might happen without the watchdog. -- [[User:Lahwaacz|Lahwaacz]] ([[User talk:Lahwaacz|talk]]) 16:42, 29 December 2016 (UTC)
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::::::Please, explain better your experience, because if you get an hardware problem that stuck your system, the '''watchdog''' should recognize this situation and it will '''automatically''' reboot the system. Without a watchdog the stuck system will continue to go (even if stuck) until you '''manually''' reboot your machine. This is the purpose of a watchdog. This is why it is not a mandatory piece of a laptop/desktop system where user can operate manually (while the user can do this in an embedded device...). --[[User:NTia89|nTia89]] ([[User talk:NTia89|talk]]) 16:53, 29 December 2016 (UTC)
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::::::Unless you have set {{ic|RuntimeWatchdogSec}} in {{ic|/etc/systemd/system.conf}}, watchdog is not doing anything for you in this case. All watchdog does in an Arch install by default is check if a shutdown has proceeded properly after 10 minutes ({{ic|1=ShutdownWatchdogSec=10m}}).  -- [[User:Rdeckard|Rdeckard]] ([[User_talk:Rdeckard|talk]]) 21:06, 30 December 2016 (UTC)
  
"''Things kinda slow? Buy more ram!''" is really not the kind of advice anyone is looking for. And the CPU section (undervolting, etc.) isn't related to speed improvements, except fan control. This section is sorely lacking a link/howto to/for BFS.<br>
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:Since you've put it on the [[Improving performance]] page, what is the performance improvement in practice? -- [[User:Lahwaacz|Lahwaacz]] ([[User talk:Lahwaacz|talk]]) 11:30, 29 December 2016 (UTC)
--[[User:Gog|Gog]] 20:36, 24 October 2009 (EDT)
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::I recorded a decrease in boot and shutdown time of about 0.1 sec over a 2.0 secs boot (systemd-analyze);
 
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::both hardware and software watchdogs are disabled; the later is 'software', so I believe it "consumes" CPU...I have no evidence about it. If you have it, share here
:To my knowledge keeping the CPU cool does not improve performance so I removed this part. I also removed the introduction about RAM. So, problems solved ?
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::PS: What I've written on the wiki is the sum/product of what I have understand/learn about kernel watchdog; an issue started time ago while for the first time I've read about "NMI_watchdog" in the dmesg; the links provided at the end of my edit are the sources from which I extrapolated those information; if you have other sources, share, I'm here to learn in primis. --[[User:NTia89|nTia89]] ([[User talk:NTia89|talk]]) 14:54, 29 December 2016 (UTC)
:[[User:Changaco|Changaco]] 11:25, 25 October 2009 (EDT)
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:::And how does that difference compare to the [https://en.wikipedia.org/wiki/Standard_deviation standard deviation] of your measured data? -- [[User:Lahwaacz|Lahwaacz]] ([[User talk:Lahwaacz|talk]]) 16:42, 29 December 2016 (UTC)
 
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::::These are already ''mean'' values and they are enough for me. If you have an easy way to compute a more detailed report, please tell me. Or better, try by yourself and share your results! --[[User:NTia89|nTia89]] ([[User talk:NTia89|talk]]) 16:53, 29 December 2016 (UTC)
::I'm not an expert, but doesn't overheating decrease performance? If it is, then preventing overheating should count as maximizing performance. If not, then the section is indeed irrelevant. I found this article saying it does for pentium 4 processors: http://www.xbitlabs.com/articles/cpu/display/p4-temp.html . But as I said I'm no expert, so what do you think?
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:I like the section and think it should be added somewhere in the Wiki. I think for now this is a reasonable place since the focus is on disabling something that may be consuming resources unnecessarily. Additionally at least 1 user has reported that the {{ic|nowatchdog}} kernel parameter did not work for them [https://bbs.archlinux.org/viewtopic.php?id=221239] and that blacklisting the module was the only way to disable watchdog.  -- [[User:Rdeckard|Rdeckard]] ([[User_talk:Rdeckard|talk]]) 14:18, 30 December 2016 (UTC)
::--Rttommy
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::Thank you, I will update the section accordingly --[[User:NTia89|nTia89]] ([[User talk:NTia89|talk]]) 14:24, 30 December 2016 (UTC)
 
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:::I'm not an expert either, maybe we should undo my change but edit in order not to present this as an absolute truth.
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:::[[User:Changaco|Changaco]] 14:13, 25 October 2009 (EDT)
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:::I think that fan control should be left in since it's generally considered to be related with overclocking. And another thing: let's keep the article's title in tandem with the heading's cases... "Maximizing Performance" or "Maximizing '''p'''erformance"? the second one matches the headings...
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:::--[[User:Gog|Gog]] 19:22, 25 October 2009 (EDT)
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:::I was wondering if we should create a script that get's the top CPU value of top and let the user choose to pause it or continue running so the system doesn't literally freeze up and become unusuable until a reboot is required, this happend to me so I was wondering if anyone else feels that this is necessary.
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:::--[[User:littlebear|littlebear]] 13:37, 6 February 2009 (EST)
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Section "The desktop switcheroo" does not make sense. [[User:Manolo|manolo]] 16:35, 7 November 2009 (EST)
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The section on btrfs talks about the libcrc32c module, but confusingly lists modules that don't seem related to btrfs. I think the zlib module is necessary, but have not yet figured out which others are or are not. [[User:Nitmd|Nitmd]] 23:27, 14 May 2010 (EDT)
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What is with the advice about glxgears framerates? "less than 300fps"... It syncs with the monitors vertical refresh rate, meaning it will only go ~60fps (or whatever your refresh rate is). [[User:PIMPinator|PIMPinator]] 11:29, 29 September 2010 (EDT)
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I read about LZO compression and space_cache for btrfs lately: http://www.phoronix.com/scan.php?page=article&item=btrfs_space_cache
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--[[User:Longint|Longint]] 18:53, 15 June 2011 (EDT)
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Firefox profile guided optimization link is useless since firefox stock builds have it enabled.
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There's no more a relative section in [[Firefox]] --[[User:Flu|Flu]] 13:46, 29 September 2011 (EDT)
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Latest revision as of 21:06, 30 December 2016

Watchdog section

I've added a watchdogs section. Tell me what do you think about? --nTia89 (talk) 10:42, 29 December 2016 (UTC)

Is it really recommended to disable watchdog services? See watchdog(8). Even when running a 'simple' desktop, it needs to monitor a lot of things. Don't forget most MB use a watchdog service. How to know this is really safe? Francoism (talk) 10:52, 29 December 2016 (UTC)
1. I've never had a problem, see also: https://bbs.archlinux.org/viewtopic.php?id=163768 --nTia89 (talk) 11:01, 29 December 2016 (UTC)
2. Your watchdog is related to the specific program watchdog (https://www.archlinux.org/packages/extra/x86_64/watchdog/), a standalone program, not installed by default, not dependency of other packages. --nTia89 (talk) 11:05, 29 December 2016 (UTC)
You are correct about the watchdog package, but it is just to give you an example of what a watchdog does. It also depends on the hardware and software that's in use. To give you an example, an USB device that causes issues, will be unable to recover if no watchdog is in use. It can also lead to unexpected reboots (a watchdog is able to perform recovery operations) and maybe even hardware damage (see temperature monitoring). The one in the kernel are linked with the CPU/MB it seems, think they are created for some reason. ;) Francoism (talk) 11:13, 29 December 2016 (UTC)
No, I don't think so. Low-level hardware interrupt are handled by low-level software, the BIOS/EFI.
For what watchdogs do, read the first and third link.
I'm with you that "if it exists, there is a good reason, so...", but this doesn't mean everybody need it.
PS: What I've written on the wiki is the sum/product of what I have understand/learn about kernel watchdog; an issue started time ago while for the first time I've read about "NMI_watchdog" in the dmesg; the links provided at the end of my edit are the sources from which I extrapolated those information; if you have other sources, share, I'm here to learn in primis. --nTia89 (talk) 14:54, 29 December 2016 (UTC)
Here is what I get from time to time after plugging someting into my only USB3 port. After that happens, I need to reboot to make it work again. It's definitely tied up to the hardware driver and I'm not really interested in finding out what might happen without the watchdog. -- Lahwaacz (talk) 16:42, 29 December 2016 (UTC)
Please, explain better your experience, because if you get an hardware problem that stuck your system, the watchdog should recognize this situation and it will automatically reboot the system. Without a watchdog the stuck system will continue to go (even if stuck) until you manually reboot your machine. This is the purpose of a watchdog. This is why it is not a mandatory piece of a laptop/desktop system where user can operate manually (while the user can do this in an embedded device...). --nTia89 (talk) 16:53, 29 December 2016 (UTC)
Unless you have set RuntimeWatchdogSec in /etc/systemd/system.conf, watchdog is not doing anything for you in this case. All watchdog does in an Arch install by default is check if a shutdown has proceeded properly after 10 minutes (ShutdownWatchdogSec=10m). -- Rdeckard (talk) 21:06, 30 December 2016 (UTC)
Since you've put it on the Improving performance page, what is the performance improvement in practice? -- Lahwaacz (talk) 11:30, 29 December 2016 (UTC)
I recorded a decrease in boot and shutdown time of about 0.1 sec over a 2.0 secs boot (systemd-analyze);
both hardware and software watchdogs are disabled; the later is 'software', so I believe it "consumes" CPU...I have no evidence about it. If you have it, share here
PS: What I've written on the wiki is the sum/product of what I have understand/learn about kernel watchdog; an issue started time ago while for the first time I've read about "NMI_watchdog" in the dmesg; the links provided at the end of my edit are the sources from which I extrapolated those information; if you have other sources, share, I'm here to learn in primis. --nTia89 (talk) 14:54, 29 December 2016 (UTC)
And how does that difference compare to the standard deviation of your measured data? -- Lahwaacz (talk) 16:42, 29 December 2016 (UTC)
These are already mean values and they are enough for me. If you have an easy way to compute a more detailed report, please tell me. Or better, try by yourself and share your results! --nTia89 (talk) 16:53, 29 December 2016 (UTC)
I like the section and think it should be added somewhere in the Wiki. I think for now this is a reasonable place since the focus is on disabling something that may be consuming resources unnecessarily. Additionally at least 1 user has reported that the nowatchdog kernel parameter did not work for them [1] and that blacklisting the module was the only way to disable watchdog. -- Rdeckard (talk) 14:18, 30 December 2016 (UTC)
Thank you, I will update the section accordingly --nTia89 (talk) 14:24, 30 December 2016 (UTC)