Messages in this thread | | | Date | Fri, 28 May 2010 17:10:20 -0700 | From | JD <> | Subject | Re: [PATCH V3] x86, UV: BAU performance and error recovery |
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On 05/28/2010 04:36 PM, Cliff Wickman wrote: > On Fri, May 28, 2010 at 03:23:21PM -0700, Greg KH wrote: > >> On Fri, May 28, 2010 at 02:43:35PM -0500, Cliff Wickman wrote: >> >>> On Fri, May 28, 2010 at 09:47:25AM -0700, Greg KH wrote: >>> >>>> On Fri, May 28, 2010 at 09:30:25AM -0700, H. Peter Anvin wrote: >>>> >>>>> On 05/28/2010 06:33 AM, Cliff Wickman wrote: >>>>> >>>>>> - adds modification of tuning variables through /proc/sgi_uv >>>>>> >>>>> Adding new directories in /proc for a proprietary architecture is >>>>> frowned upon, to put it mildly. At the very least try to find a place >>>>> in sysfs for it. >>>>> >>>>> [Cc: gregkh in order to find a place in sysfs] >>>>> >>>> Hm, what type of files are you needing here? Do they corrispond with >>>> any specific hardware devices? If so, just put them on the hardware >>>> devices in sysfs. >>>> >>>> thanks, >>>> >>>> greg k-h >>>> >>> There is an SGI-specific directory in sysfs: /sys/firmware/sgi_uv >>> though the tuning variables for the handling of the hardware Broadcast >>> Assist Unit don't fit there very logically. >>> >>> The BAU's statistics are already displayed through the UV-only >>> /proc/sgi_uv/ptc_statistics. This was deemed necessary because of the >>> potentially very large size of that file --- it is still true that a /sys file >>> is limited to one page, is it not? >>> >> It is limited to one single value, which would never be larger than a >> page, so yes, it is limited to one page. >> >> What kind of information are you showing here? Should this thing just >> be in debugfs instead? You can do whatever you want there. >> >> thanks, >> >> greg k-h >> > /proc/sgi_uv/bau_tunables would be a read/write file to display and change > nine threshold and delay values for tuning the BAU driver. > > I like debugfs, except that a distro may not build the kernel with it > configured on. The tunables should be available as administrative > options on a customer kernel, not just as a development tool. > > And in our case the distros are already building with other such writable > options in /proc/sgi_uv. We'd like to postpone a wholesale move of such > options (assuming there will be some better place) and stay with the existing > location for this release. > > I know we (the community) would like to move non-process info out of /proc. > It seems to me that we need a similar filesystem for large and/or > administrative files. That's my perspective. > > -Cliff > Would the similar filesystem you propose be backed by permanent storage, unlike /proc?
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