Van de Ven: Introducing 'timechart' [LWN.net]

Arjan van de Ven introduces a new tool, called "timechart" on his weblog. Timechart is meant to help visualize and diagnose latency problems in a running Linux system. "To solve this, I have been working on a new tool, called Timechart, based on 'perf', that has the objective to show on a system level what is going on, at various levels of detail. In fact, one of the design ideas behind timechart is that the output should be 'infinitely zoomable'; that is, if you want to know more details about something, you should be able to zoom in to get these details."

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van de Ven: Introducing 'timechart'

Posted Sep 15, 2009 3:04 UTC (Tue) by NightMonkey (subscriber, #23051) [Link] (7 responses)

OK, I'll bite. Where is the link to the program source?

van de Ven: Introducing 'timechart'

Posted Sep 15, 2009 4:04 UTC (Tue) by arjan (subscriber, #36785) [Link] (6 responses)

it was posted to lkml a few days ago; it's unfortunately not yet just "download a bit of userspace program", it includes some kernel infrastructure patches as well.

van de Ven: Introducing 'timechart'

Posted Sep 15, 2009 6:10 UTC (Tue) by NightMonkey (subscriber, #23051) [Link]

Thank you for the info. Gosh it is nice to have LWN around. :)

van de Ven: Introducing 'timechart'

Posted Sep 15, 2009 8:59 UTC (Tue) by mjthayer (guest, #39183) [Link] (4 responses)

Is this something that distributions are likely to be happy enabling by default? I gather that that was not the case for latencytop, and it would really be a shame if timechart wasn't used as widely as it might be.

van de Ven: Introducing 'timechart'

Posted Sep 15, 2009 9:08 UTC (Tue) by mingo (subscriber, #31122) [Link]

Yes, since it's an extension/usage of performance counters, it should be present in distributions that have perfcounters enabled.

In fact since it's a new sub-command of tools/perf/ it will get into those distributions automatically, once they update to a kernel that includes these bits.

So "perf timechart" should show up in a distro near you.

van de Ven: Introducing 'timechart'

Posted Sep 15, 2009 11:04 UTC (Tue) by arjan (subscriber, #36785) [Link] (2 responses)

the distros I use (moblin and fedora) both have latencytop on
I'm not aware of any distro that doesn't have it on...

van de Ven: Introducing 'timechart'

Posted Sep 15, 2009 14:28 UTC (Tue) by dtlin (subscriber, #36537) [Link] (1 responses)

Debian does not ship with a latencytop-enabled kernel:
http://bugs.debian.org/478739

van de Ven: Introducing 'timechart'

Posted Sep 22, 2009 11:03 UTC (Tue) by johnflux (guest, #58833) [Link]

The reason appears to be that this option introduces too many debug options, which debian does not like to enable by default.

obSurnameCapitalisation:

Posted Sep 15, 2009 6:03 UTC (Tue) by paulj (subscriber, #341) [Link] (5 responses)

Name 'glue' (I don't the technical name) - such as 'van' ('of'), 'de{,n,r}' ('the'), 'van de{,n,r}' ('of the'), 'of' ('or') - is normally not capitalised in Dutch, just as in english (surprise surprise given how closely related the languages are). However, the normal rule that sentences should start with a capital letter still applies. Hence, the article title should be:

Van de Ven: etc..

obSurnameCapitalisation:

Posted Sep 15, 2009 7:25 UTC (Tue) by shalem (subscriber, #4062) [Link] (2 responses)

Actually,

If the sir name is used without a first name in front of it, the "glue" should be capitalized even if not in the beginning of a sentence, at least
in Dutch. Dunno what should be done when using a Dutch sir name in an English
sentence :)

Regards,

Hans de Goede

obSurnameCapitalisation:

Posted Sep 15, 2009 15:19 UTC (Tue) by mjw (subscriber, #16740) [Link] (1 responses)

> Dunno what should be done when using a Dutch sir name in an English sentence :)

The rules are confusing since even between Dutch language speakers there is a difference of when to capitalize the "tussenvoegsels". For example a Belgium name will always have a capital (or two), but Dutch names won't unless at the start of a sentence, or after an introductory phrase.

http://www.onzetaal.nl/advies/tussenvoegsel.php

So, to get it correct you also need to know the customs of the country of birth of the person :)

obSurnameCapitalisation:

Posted Sep 15, 2009 16:05 UTC (Tue) by jordanb (guest, #45668) [Link]

The Chicago Manual says this on the subject of Dutch names:

Section 8.13 Dutch Names:
> In english usage, the particles van, van den, ter, and the like are lowercased when full names are given but usually capitalized when only the last name is used.

> Joannes van Keulen; Van Keulen
> Pieter van den Keere; Van den Keere
> Vincent van Gogh; Van Gogh
> Gerard ter Borch; Ter Borch

obSurnameCapitalisation:

Posted Sep 15, 2009 13:22 UTC (Tue) by jake (editor, #205) [Link] (1 responses)

> However, the normal rule that sentences should start with a capital
> letter still applies.

Thanks for the heads up. I fixed the title and will remember when using Arjan's (or others) last name in articles as it appears that any use of the last name (without the first name or initial) should be capitalized.

jake

obSurnameCapitalisation:

Posted Sep 19, 2009 1:02 UTC (Sat) by gerdesj (subscriber, #5446) [Link]

... but jake (sic) why not also use the conventions of your own language and capitalize that J!

I assume that your own language is English of some sort.

Me? I like my J

Cheers
Jon

Van de Ven: Introducing 'timechart'

Posted Sep 15, 2009 16:02 UTC (Tue) by zsouthboy (guest, #60295) [Link] (1 responses)

This is fantastic, attempting to figure out what is happening at any point in time is quite hard, but showing that visually is so useful. I can't wait to use this. Troubleshooting stalls and other complaints, yay! Thank you Arjan!

Van de Ven: Introducing 'timechart'

Posted Sep 18, 2009 18:31 UTC (Fri) by oak (guest, #2786) [Link]

> This is fantastic, attempting to figure out what is happening at any
> point in time is quite hard, but showing that visually is so useful.

Btw. While Ftrace is interesting, if you're trying to debug what happens
in the whole system, at the moment LTT and its visualizer are much more
useful: http://lttng.org/.

This short paper describes the differences between LTT and ftrace:
http://events.linuxfoundation.org/archive/lfcs09_desnoyer...

(Disclaimer: I'm a satisfied LTT user, and have used it before there even
was ftrace.)