Re: [PATCH v2] trace-cmd: remove ununsed knuth_hash*() routines

["Yordan Karadzhov (VMware)" <y.karadz@gmail.com>]

On 29.06.19 г. 9:27 ч., Greg Thelen wrote:
> Neither 16-bit knuth_hash16() nor the 32-bit knuth_hash() are used.
> Delete them both.
> 
> And rename the remaining function: knuth_hash8() => knuth_hash()
> 

Thanks!

Reviewed-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>


> Signed-off-by: Greg Thelen <gthelen@google.com>
> ---
>   kernel-shark/src/libkshark.c      | 12 +++++-----
>   lib/trace-cmd/trace-filter-hash.c | 40 +++++++------------------------
>   2 files changed, 14 insertions(+), 38 deletions(-)
> 
> diff --git a/kernel-shark/src/libkshark.c b/kernel-shark/src/libkshark.c
> index 0f0a1bab4d5c..d2764e813194 100644
> --- a/kernel-shark/src/libkshark.c
> +++ b/kernel-shark/src/libkshark.c
> @@ -252,13 +252,13 @@ void kshark_free(struct kshark_context *kshark_ctx)
>   	free(kshark_ctx);
>   }
>   
> -static inline uint8_t knuth_hash8(uint32_t val)
> +static inline uint8_t knuth_hash(uint32_t val)
>   {
>   	/*
> -	 * Hashing functions, based on Donald E. Knuth's Multiplicative
> -	 * hashing. See The Art of Computer Programming (TAOCP).
> -	 * Multiplication by the Prime number, closest to the golden
> -	 * ratio of 2^8.
> +	 * Small table hashing function adapted from Donald E. Knuth's 32 bit
> +	 * multiplicative hash.  See The Art of Computer Programming (TAOCP).
> +	 * Multiplication by the Prime number, closest to the golden ratio of
> +	 * 2^8.
>   	 */
>   	return UINT8_C(val) * UINT8_C(157);
>   }
> @@ -282,7 +282,7 @@ kshark_add_task(struct kshark_context *kshark_ctx, int pid)
>   	struct kshark_task_list *list;
>   	uint8_t key;
>   
> -	key = knuth_hash8(pid);
> +	key = knuth_hash(pid);
>   	list = kshark_find_task(kshark_ctx, key, pid);
>   	if (list)
>   		return list;
> diff --git a/lib/trace-cmd/trace-filter-hash.c b/lib/trace-cmd/trace-filter-hash.c
> index 39b28790e0bc..45ca68c2959e 100644
> --- a/lib/trace-cmd/trace-filter-hash.c
> +++ b/lib/trace-cmd/trace-filter-hash.c
> @@ -14,45 +14,21 @@
>   
>   #define FILTER_HASH_SIZE	256
>   
> -/*
> - * Hashing functions, based on Donald E. Knuth's Multiplicative hashing.
> - * See The Art of Computer Programming (TAOCP).
> - */
> -
> -static inline uint8_t knuth_hash8(uint32_t val)
> +static inline uint8_t knuth_hash(uint32_t val)
>   {
>   	/*
> -	 * Multiplicative hashing function.
> -	 * Multiplication by the Prime number, closest to the golden
> -	 * ratio of 2^8.
> +	 * Small table hashing function adapted from Donald E. Knuth's 32 bit
> +	 * multiplicative hash.  See The Art of Computer Programming (TAOCP).
> +	 * Multiplication by the Prime number, closest to the golden ratio of
> +	 * 2^8.
>   	 */
>   	return UINT8_C(val) * UINT8_C(157);
>   }
>   
> -static inline uint16_t knuth_hash16(uint32_t val)
> -{
> -	/*
> -	 * Multiplicative hashing function.
> -	 * Multiplication by the Prime number, closest to the golden
> -	 * ratio of 2^16.
> -	 */
> -	return UINT16_C(val) * UINT16_C(40507);
> -}
> -
> -static inline uint32_t knuth_hash(uint32_t val)
> -{
> -	/*
> -	 * Multiplicative hashing function.
> -	 * Multiplication by the Prime number, closest to the golden
> -	 * ratio of 2^32.
> -	 */
> -	return val * UINT32_C(2654435761);
> -}
> -
>   struct tracecmd_filter_id_item *
>   tracecmd_filter_id_find(struct tracecmd_filter_id *hash, int id)
>   {
> -	int key = knuth_hash8(id);
> +	int key = knuth_hash(id);
>   	struct tracecmd_filter_id_item *item = hash->hash[key];
>   
>   	while (item) {
> @@ -66,7 +42,7 @@ tracecmd_filter_id_find(struct tracecmd_filter_id *hash, int id)
>   
>   void tracecmd_filter_id_add(struct tracecmd_filter_id *hash, int id)
>   {
> -	int key = knuth_hash8(id);
> +	int key = knuth_hash(id);
>   	struct tracecmd_filter_id_item *item;
>   
>   	item = calloc(1, sizeof(*item));
> @@ -81,7 +57,7 @@ void tracecmd_filter_id_add(struct tracecmd_filter_id *hash, int id)
>   
>   void tracecmd_filter_id_remove(struct tracecmd_filter_id *hash, int id)
>   {
> -	int key = knuth_hash8(id);
> +	int key = knuth_hash(id);
>   	struct tracecmd_filter_id_item **next = &hash->hash[key];
>   	struct tracecmd_filter_id_item *item;
>   
>