Re: [PATCH][1/7] perfctr-2.7.2 for 2.6.6-mm2: core

From: Andrew Morton
Date: Fri May 14 2004 - 17:58:11 EST

Mikael Pettersson <mikpe@xxxxxxxxx> wrote:
> - core driver files and kernel changes

Looks like we need six system calls if we're going to do it that way.

All that marshalling and unmarshalling code is a bit evil. I wonder if
there's some way in which it can be flattened out.

One option would be to present all the info to userspace as a virtual
filesystem, although it would be a bit weird that the contents of the
"files" depends upon the process which reads them.

Maybe a mkdir() on that filesystem could create a directory which contains
files which contain the counters for the process which made the directory?
The directory would need to be auto-rmdir'ed on process exit. It's
basically the same semantics as /proc/pid.

But /proc/pid can be read by processes other than "pid". Does the same
apply to the perfcntr instrumentation? (Being able to read another
process's perfcntr info sounds useful. Is it?)

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at