linux-kernel - Re: [BUG] Strange 1-second pauses during Resume-from-RAM

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20071202204559.GA28550@elte.hu>
Date:	Sun, 2 Dec 2007 21:45:59 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Jörn Engel <joern@...fs.org>
Cc:	Mark Lord <lkml@....ca>, Pavel Machek <pavel@....cz>,
	Mark Lord <liml@....ca>, Thomas Gleixner <tglx@...utronix.de>,
	len.brown@...el.com, Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, linux-pm@...ts.linux-foundation.org,
	rjw@...k.pl
Subject: Re: [BUG] Strange 1-second pauses during Resume-from-RAM


* Jörn Engel <joern@...fs.org> wrote:

> > oprofile helps if you can reliably reproduce the slowdown in a loop 
> > or for a long amount of time, with lots of CPU utilization - and 
> > then it's also lower overhead. The tracer can be used to capture 
> > rare or complex events, and gives the full flow control and what is 
> > happening within the kernel.
> 
> Such a trace would be useful indeed.  But so far the patch has only 
> given me grief and nothing remotely like useful output.  Maybe I 
> should simply use the complete -rt patch instead of debugging the 
> broken-out latency-tracer patch.

to capture that trace i did not use -rt, i just patched latest -git 
with:

  http://people.redhat.com/mingo/latency-tracing-patches/latency-tracing-v2.6.24-rc3.combo.patch

(this has your fixes included already)

have done:

  echo 1 > /proc/sys/kernel/mcount_enabled

and have run:

  ./trace-cmd sleep 1 > trace.txt

  http://people.redhat.com/mingo/latency-tracing-patches/trace-cmd.c

to capture a 1 second trace of what the system is doing. I think your 
troubles are due to running it within a qemu guest - that is not a 
typical utilization so you are on unchartered waters.

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/