Messages in this thread | | | Date | Fri, 03 Oct 2014 15:10:51 +0200 | From | Nicolas Dichtel <> | Subject | Re: [RFC PATCH linux 2/2] fs/proc: use a hash table for the directory entries |
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Le 02/10/2014 18:46, Stephen Hemminger a écrit : > On Thu, 2 Oct 2014 17:25:01 +0200 > Nicolas Dichtel <nicolas.dichtel@6wind.com> wrote: > >> From: Thierry Herbelot <thierry.herbelot@6wind.com> >> >> The current implementation for the directories in /proc is using a single >> linked list. This is slow when handling directories with large numbers of >> entries (eg netdevice-related entries when lots of tunnels are opened). >> >> This patch enables multiple linked lists. A hash based on the entry name is >> used to select the linked list for one given entry. >> >> The speed creation of netdevices is faster as shorter linked lists must be >> scanned when adding a new netdevice. >> >> Here are some numbers: >> >> dummy30000.batch contains 30 000 times 'link add type dummy'. >> >> Before the patch: >> time ip -b dummy30000.batch >> real 2m32.221s >> user 0m0.380s >> sys 2m30.610s >> >> After the patch: >> time ip -b dummy30000.batch >> real 1m57.190s >> user 0m0.350s >> sys 1m56.120s >> >> The single 'subdir' list head is replaced by a subdir hash table. The subdir >> hash buckets are only allocated for directories. The number of hash buckets >> is a compile-time parameter. >> >> For all functions which handle directory entries, an additional check on the >> directory nature of the dir entry ensures that pde_hash_buckets was allocated. >> This check was not needed as subdir was present for all dir entries, whether >> actual directories or simple files. >> >> Signed-off-by: Thierry Herbelot <thierry.herbelot@6wind.com> >> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> > > I think the speed up is a good idea and makes sense. > It would be better to use exist hlist macros for hash table rather than > open coding it. > Right, I will rework this after looking at rbtree. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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