Re: [ANNOUNCE] kmemcheck v7

[John Reiser]

Vegard Nossum wrote:
> How is the speed of Valgrind+UML, does anybody know?

The speed of Valgrind+UML is the same as the speed of valgrind
on any application.  On a 2GHz box it took about 2.5 minutes
to reach "login:" from a cold boot of UML (includes udev, etc.)
So if normal boot takes 15 seconds, then that's a factor of 10
slowdown: slow for interactivity, yet bearable for checking.
The memory-intensive portions (linear search, pointer chasing,
etc.) can be slower still, but loops that concentrate on
register arithmetic or conditional branching go faster.
There is almost no system wait time: normal device delays (disk,
network) get totally overlapped by CPU usage for grinding :-)

I'd like to have both kmemcheck and valgrind+UML, and use them
differently.  Run kmemcheck all the time on a box or two as
"background trolling" for infrequent cases.  Use valgrind+UML
for interactivity and programmable flexibility when hunting
specific bugs, or when hardware cannot be dedicated.

-- 
John Reiser, jreiser@xxxxxxxxxxxx
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