x86, UV: BAU performance and error recovery
in [Kernel]
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From: Cliff Wickman on 28 May 2010 19:40 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 -- Cliff Wickman SGI cpw(a)sgi.com (651) 683-3824 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Greg KH on 28 May 2010 20:20 On Fri, May 28, 2010 at 06:36:23PM -0500, Cliff Wickman wrote: > /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. All distros have debugfs turned on now, and mounted, due to the perf interface there, as well as a lot of other good debug information that is present. So you don't have to worry about that. > 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. So because some distro took a non-upstream patch, you want upstream to accept the patch despite it being the incorrect place to put such a file? Heh, you might want to rethink that... > I know we (the community) would like to move non-process info out of /proc. Yes. We also don't want new files added there that are not dealing with processes. > It seems to me that we need a similar filesystem for large and/or > administrative files. That's my perspective. I do not know of any other such "large administrative" file that needs to be added to the system at such a time, becides this one, do you? So please, just put it in debugfs. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: JD on 28 May 2010 20:20 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? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Cliff Wickman on 31 May 2010 15:50 On Fri, May 28, 2010 at 05:05:26PM -0700, Greg KH wrote: > On Fri, May 28, 2010 at 06:36:23PM -0500, Cliff Wickman wrote: > > /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. > > All distros have debugfs turned on now, and mounted, due to the perf > interface there, as well as a lot of other good debug information that > is present. > > So you don't have to worry about that. Good to hear. That makes the choice simple. > .... > > So please, just put it in debugfs. > > thanks, > > greg k-h Okay. I moved the file to debugfs, and will re-submit the patch momentarily. -Cliff -- Cliff Wickman SGI cpw(a)sgi.com (651) 683-3824 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Cliff Wickman on 31 May 2010 16:20
On Fri, May 28, 2010 at 05:10:20PM -0700, JD wrote: > > > 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? I withdraw my proposal for any new filesystem type, as debugfs works fine for what I'm talking about, as long as it is configured on by all the distributions. No, a permanent storage backed filesystem was not what I had in mind. -- Cliff Wickman SGI cpw(a)sgi.com (651) 683-3824 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |