Messages in this thread | | | Date | Tue, 29 Mar 2011 17:56:14 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] bitmap, irq: Add smp_affinity_list interface to /proc/irq |
| |
On Tue, 29 Mar 2011 17:51:18 -0700 Mike Travis <travis@sgi.com> wrote:
> > > > Also, the patch adds a new interface which duplicates an existing one, > > only the formats are different, yes? This is, of course, bad. > > > > The only justification we've seen for being bad is "Manually adjusting > > the smp_affinity for IRQ's becomes unwieldy when the cpu count is > > large". A more thorough description of how painful this is might help > > motivate people to do bad things to the kernel. > > > > Also, if it's just a matter of an alternative presentation of the data, > > why not implement the desired user interface with a little userspace > > tool then feed the results down into the existing kernel interface? > > > > Setting smp affinity to cpus 256 to 263 would be: > > echo 000000ff,00000000,00000000,00000000,00000000,00000000,00000000,00000000 > smp_affinity > > instead of: > > echo 256-263 > smp_affinity_list > > Think about what it looks like for cpus around say, 4088 to 4095. > > We already have many alternate "list" interfaces: > > /sys/devices/system/cpu/cpuX/indexY/shared_cpu_list > /sys/devices/system/cpu/cpuX/topology/thread_siblings_list > /sys/devices/system/cpu/cpuX/topology/core_siblings_list > /sys/devices/system/node/nodeX/cpulist > /sys/devices/pci***/***/local_cpulist > > etc. > > This just expands on that same philosophy.
You mean that if someone had written a stupid little tool to convert a list of tuples into a bitmap, we wouldn't have needed to add all that crap to the kernel?
| |