Re: [dpdk-dev] [PATCH] replaced O(n^2) sort in sort_by_physaddr() with qsort() from standard library

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi Jay,

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Jay Rolette
> Sent: Thursday, December 11, 2014 4:06 PM
> To: Dev
> Subject: [dpdk-dev] [PATCH] replaced O(n^2) sort in sort_by_physaddr() with qsort() from standard library
> 
> Signed-off-by: Jay Rolette <rolette@infiniteio.com>

The patch itself looks good to me.
Though it seems something wrong with formatting - all lines start with offset 0.
Probably your mail client?
Konstantin


> ---
>  lib/librte_eal/linuxapp/eal/eal_memory.c | 59
> +++++++++++---------------------
>  1 file changed, 20 insertions(+), 39 deletions(-)
> 
> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c
> b/lib/librte_eal/linuxapp/eal/eal_memory.c
> index bae2507..3656515 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
> @@ -670,6 +670,25 @@ error:
>   return -1;
>  }
> 
> +static int
> +cmp_physaddr(const void *a, const void *b)
> +{
> +#ifndef RTE_ARCH_PPC_64
> + const struct hugepage_file *p1 = (const struct hugepage_file *)a;
> + const struct hugepage_file *p2 = (const struct hugepage_file *)b;
> +#else
> + // PowerPC needs memory sorted in reverse order from x86
> + const struct hugepage_file *p1 = (const struct hugepage_file *)b;
> + const struct hugepage_file *p2 = (const struct hugepage_file *)a;
> +#endif
> + if (p1->physaddr < p2->physaddr)
> + return -1;
> + else if (p1->physaddr > p2->physaddr)
> + return 1;
> + else
> + return 0;
> +}
> +
>  /*
>   * Sort the hugepg_tbl by physical address (lower addresses first on x86,
>   * higher address first on powerpc). We use a slow algorithm, but we won't
> @@ -678,45 +697,7 @@ error:
>  static int
>  sort_by_physaddr(struct hugepage_file *hugepg_tbl, struct hugepage_info
> *hpi)
>  {
> - unsigned i, j;
> - int compare_idx;
> - uint64_t compare_addr;
> - struct hugepage_file tmp;
> -
> - for (i = 0; i < hpi->num_pages[0]; i++) {
> - compare_addr = 0;
> - compare_idx = -1;
> -
> - /*
> - * browse all entries starting at 'i', and find the
> - * entry with the smallest addr
> - */
> - for (j=i; j< hpi->num_pages[0]; j++) {
> -
> - if (compare_addr == 0 ||
> -#ifdef RTE_ARCH_PPC_64
> - hugepg_tbl[j].physaddr > compare_addr) {
> -#else
> - hugepg_tbl[j].physaddr < compare_addr) {
> -#endif
> - compare_addr = hugepg_tbl[j].physaddr;
> - compare_idx = j;
> - }
> - }
> -
> - /* should not happen */
> - if (compare_idx == -1) {
> - RTE_LOG(ERR, EAL, "%s(): error in physaddr sorting\n", __func__);
> - return -1;
> - }
> -
> - /* swap the 2 entries in the table */
> - memcpy(&tmp, &hugepg_tbl[compare_idx],
> - sizeof(struct hugepage_file));
> - memcpy(&hugepg_tbl[compare_idx], &hugepg_tbl[i],
> - sizeof(struct hugepage_file));
> - memcpy(&hugepg_tbl[i], &tmp, sizeof(struct hugepage_file));
> - }
> + qsort(hugepg_tbl, hpi->num_pages[0], sizeof(struct hugepage_file),
> cmp_physaddr);
>   return 0;
>  }
> 
> --