Guenter Roeck <groeck@xxxxxxxxxxx> writes: > There are two key elements affecting performance when creating large > numbers of interfaces: > - full_name_hash() doesn't do a good job in selecting hash buckets > - sysfs uses a linked list to store directory entries, and strcmp() to > compare entries. > > The sysfs problem may be solved with Eric's sysfs upcoming changes; if > not, there are (at least) two ways to improve sysfs performance: I have not addressed the slowdown problem. But it is good to hear that it exists and that people care. I thought sysfs was going to slow things down. My immediate goal is to reduce the locking complexity to that found within /proc. > 1) store a name hash with each entry, and compare the hash result before > comparing the entire name > 2) create a per-directory hash table. > > full_name_hash() can be improved by replacing the hash, for example as > follows. > Old: > return (prevhash + (c << 4) + (c >> 4)) * 11; > New: > return (prevhash + c) * 41; At least with the sanity checking turned on. sysctl will also have slowdowns that are more significant than sysfs when creating network devices. So that should be addressed as well. Eric _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
