On 2/16/16 5:37 PM, Edward Cree wrote:
On 16/02/16 23:55, Greg Kroah-Hartman wrote:
On Tue, Feb 16, 2016 at 11:46:49PM +0000, Edward Cree wrote:
Sorry if this has been suggested before, but if so I couldn't find it.
Short version: could a sysfs dir reference a list of default attributes
rather than having to instantiate them all?
Shorter version, why do you think it is? :)
Have you done some testing of the amount of memory that sysfs entries
consume and found any problems with it?
Two reasons:
a) in his netdev1.1 talk "Scaling the Number of Network Interfaces on
Linux",
David Ahern claimed a memory overhead of (iirc) about 45kB per
netdevice,
of which he attributed (again, iirc) about 20kB to sysfs entries. He
also
indicated that this was a problem for his use case. (My apologies to
David if I've misrepresented him. CCed him so he can correct me.)
Close enough. :-)
I analyzed memory allocations for the creation of a dummy netdevice. All
total 36,450 bytes were requested resulting in 43,944 bytes allocated.
Of that kobject and sysfs is 14,568. So kobject and sysfs is roughly 1/3
the memory overhead of a netdevice and is also a significant overhead in
the time to create the netdevice.
David
