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Re: [PATCH 08/11] libihash: reduce the default maximum load factor to 75
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From: |
Samuel Thibault |
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Subject: |
Re: [PATCH 08/11] libihash: reduce the default maximum load factor to 75% |
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Date: |
Mon, 12 May 2014 12:38:25 +0200 |
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User-agent: |
Mutt/1.5.21+34 (58baf7c9f32f) (2010-12-30) |
Justus Winter, le Mon 12 May 2014 12:35:08 +0200, a écrit :
> The performance of hash tables depend critically on a low number of
> hash collisions. As the table fills up, the chance of collisions
> necessarily raises.
>
> Previously, libihash resized the hash table when the load exceeded
> 80%. This seems a bit optimistic (e. g. java.util.Hashtable uses 75%
> as default).
Ack.
> * libihash/ihash.h (HURD_IHASH_MAX_LOAD_DEFAULT): Set to 75.
> ---
> libihash/ihash.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libihash/ihash.h b/libihash/ihash.h
> index 3ca5ec3..6bdc925 100644
> --- a/libihash/ihash.h
> +++ b/libihash/ihash.h
> @@ -94,7 +94,7 @@ typedef struct hurd_ihash *hurd_ihash_t;
> /* Construction and destruction of hash tables. */
>
> /* The default value for the maximum load factor in percent. */
> -#define HURD_IHASH_MAX_LOAD_DEFAULT 80
> +#define HURD_IHASH_MAX_LOAD_DEFAULT 75
>
> /* The LOCP_OFFS to use if no location pointer is available. */
> #define HURD_IHASH_NO_LOCP INTPTR_MIN
> --
> 2.0.0.rc0
>
--
Samuel
***e trouve un .xls
***e passe un moment à se demander quelle version de xml c'est ça, le .xls
e: donc j'ai fait un file....
-+- #sos - on n'a pas forcément les mêmes références que tout le monde -+-
- Re: [PATCH 02/11] libports: use a single hash table, (continued)
[PATCH 04/11] libports: lock-less reference counting for port_info objects, Justus Winter, 2014/05/12
[PATCH 08/11] libihash: reduce the default maximum load factor to 75%, Justus Winter, 2014/05/12
[PATCH 11/11] fatfs: improve {enable,disable}_caching, Justus Winter, 2014/05/12
[PATCH 10/11] ext2fs: improve {enable,disable}_caching, Justus Winter, 2014/05/12
[PATCH 09/11] libihash: use linear probing and fast modulo operation, Justus Winter, 2014/05/12
Re: [PATCH 01/11] ext2fs: cache the superblock, Samuel Thibault, 2014/05/12