Messages in this thread | | | Date | Wed, 20 Dec 2006 00:40:57 -0500 | From | "Albert Cahalan" <> | Subject | Re: [PATCH] procfs: export context switch counts in /proc/*/stat |
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David Wragg writes: > Benjamin LaHaise <bcrl@kvack.org> writes: >> On Mon, Dec 18, 2006 at 11:50:08PM +0000, David Wragg wrote:
>>> This patch (against 2.6.19/2.6.19.1) adds the four context >>> switch values (voluntary context switches, involuntary >>> context switches, and the same values accumulated from >>> terminated child processes) to the end of /proc/*/stat, >>> similarly to min_flt, maj_flt and the time used values.
Hmmm, OK, do people have a use for these values?
>> Please put these into new files, as the stat files in /proc are >> horribly overloaded and have always been somewhat problematic >> when it comes to changing how things are reported due to internal >> changes to the kernel. Cheers,
No thanks. Yours truly, the maintainer of "ps", "top", "vmstat", etc.
> The delay accounting value was added to the end of /proc/pid/stat back > in July without discussion, so I assumed this approach was still > considered satisfactory.
/proc/*/stat is the very best place in /proc for any per-process data that will be commonly needed. Unlike /proc/*/status, few people are tempted to screw with the formatting and/or spelling. Unlike the /sys crap, it doesn't take 3 syscalls PER VALUE to get at the data.
The things to ask are of course: will this really be used, and does it really belong in /proc at all?
> Putting just these four values into a new file would seem a little > odd, since they have a lot in common with the other getrusage values > that are already in /proc/pid/stat. One possibility is to add > /proc/pid/rusage, mirroring the full struct rusage in text form, since > struct rusage is already part of the kernel ABI (though Linux doesn't > fill in half of the values).
Since we already have a struct defined and all...
sys_get_rusage(int pid)
> Or perhaps it makes sense to reorganize all the values from > /proc/pid/stat and its siblings into a sysfs-like one-value-per-file > structure, though that might introduce atomicity and efficiency issues > (calculating some of the values involves iterating over the threads in > the process; with everything in one file, these loops are folded > together).
Yeah, big time. Things are quite bad in /proc, but /sys is a joke. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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