I applied your basic ideas with some slightly different logic
this will be in the next release
#define VMPAGESIZE 8192
#if _AST_PAGESIZE > VMPAGESIZE
#undef VMPAGESIZE
#define VMPAGESIZE _AST_PAGESIZE
#endif
#if _lib_getpagesize && !defined(_AST_PAGESIZE)
#define GETPAGESIZE(x) ((x) ? (x) : \
(((x)=getpagesize()) < VMPAGESIZE ? ((x)=VMPAGESIZE) :
(x)) )
#else
#define GETPAGESIZE(x) ((x) = VMPAGESIZE)
#endif
#ifdef _AST_PAGESIZE
#define VMHEAPINCR (_Vmpagesize*1)
#else
#define VMHEAPINCR (_Vmpagesize*4)
#endif
On Sat, 18 Jul 2009 11:02:41 +0200 Roland Mainz wrote:
> Hi!
> ----
> I've been looking for a way to reduce the startup time of libast-based
> applications. I've got some benchmarking feedback back from Sun staff
> which indicates that the runtime of a simple piece of code like:
> -- snip --
> int main(int ac, char *av[])
> {
> return b_mkdir(ac, av, NULL);
> }
> -- snip --
> ... needs approximately _twice_ the execution time of the current native
> command (see
> http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/cmd/mkdir/mkdir.c).
> After some digging I found this:
> The number of lines returned by /usr/bin/truss is ~~47 lines for the old
> code vs. ~~62 lines for the new code. The difference can be broken down
> to this:
> 1. One extra call to |sysconfig(_CONFIG_PAGESIZE)|
> 2. Four extra calls to |brk()|
> 3. Ten various calls to load libast+libcmd
> [3] isn't really fixable
> [1] and [2] can be eliminated by the following patch and setting
> |_AST_PAGESIZE| to 65536 on Solaris/SPARC:
> -- snip --
> Index: common/vmalloc/vmhdr.h
> ===================================================================
> --- common/vmalloc/vmhdr.h (revision 1620)
> +++ common/vmalloc/vmhdr.h (working copy)
> @@ -161,7 +161,7 @@
> #undef VMPAGESIZE
> #define VMPAGESIZE _AST_PAGESIZE
> #endif
> -#if _lib_getpagesize
> +#if defined(_lib_getpagesize) && !defined(VMPAGESIZE)
> #define GETPAGESIZE(x) ((x) ? (x) : \
> (((x)=getpagesize()) < VMPAGESIZE ?
> ((x)=VMPAGESIZE) : (x)) )
> #else
> -- snip --
> [2] is elimited because in the current code the initial heap size is set
> to the page size in "vmprivate.c" like this...
> -- snip --
> 79 if(vd->incr <= 0) /* this is just _Vmheap on the first call */
> 80 vd->incr = _Vmpagesize;
> -- snip --
> ... however the peak memory consumtion of a command like $ cut --man #
> has a peak consumtion of around 28k which requires multiple |brk()|
> calls. Bumping either the allocator page size to a higher value _xor_
> replacing the line above with |vd->incr = _Vmpagesize*4;| fixes this.
> After some more thinking I came up with the following diff:
> -- snip --
> Index: common/vmalloc/vmprivate.c
> ===================================================================
> --- common/vmalloc/vmprivate.c (revision 1620)
> +++ common/vmalloc/vmprivate.c (working copy)
> @@ -77,7 +77,7 @@
> #endif
>
> if(vd->incr <= 0) /* this is just _Vmheap on the first call */
> - vd->incr = _Vmpagesize;
> + vd->incr = INITIAL_VMHEAP_SIZE;
>
> /* Get slightly more for administrative data */
> s = size + sizeof(Seg_t) + sizeof(Block_t) + sizeof(Head_t) +
> 2*ALIGN;
> Index: common/vmalloc/vmhdr.h
> ===================================================================
> --- common/vmalloc/vmhdr.h (revision 1620)
> +++ common/vmalloc/vmhdr.h (working copy)
> @@ -161,12 +161,15 @@
> #undef VMPAGESIZE
> #define VMPAGESIZE _AST_PAGESIZE
> #endif
> -#if _lib_getpagesize
> +#if defined(_lib_getpagesize) && !defined(VMPAGESIZE)
> #define GETPAGESIZE(x) ((x) ? (x) : \
> (((x)=getpagesize()) < VMPAGESIZE ?
> ((x)=VMPAGESIZE) : (x)) )
> #else
> #define GETPAGESIZE(x) ((x) = VMPAGESIZE)
> #endif
> +#ifndef INITIAL_VMHEAP_SIZE
> +#define INITIAL_VMHEAP_SIZE ((_Vmpagesize)*4)
> +#endif
>
> /* Blocks are allocated such that their sizes are 0%(BITS+1)
> ** This frees up enough low order bits to store state information
> -- snip --
> This gives us two possible ways for tuning:
> 1. Setting |_AST_PAGESIZE| will define a static page size, avoiding the
> (quite expensive) |sysconfig(_CONFIG_PAGESIZE)| call
> 2. The initial heap allocator size of now defined via
> |INITIAL_VMHEAP_SIZE| and set to four times the default page size -
> which is 4*8192 bytes on Solaris/SPARC and enougth that a plain $ cut
> --man # call only needs one single |brk()| call. I've made this an extra
> macro to control the value since an alternative solution may be to set
> |_AST_PAGESIZE| to 64k (which allows to make active use of 64k MMU pages
> on SPARC) and setting |INITIAL_VMHEAP_SIZE| to ((_Vmpagesize)*1) (since
> 4*64k would be too large as initial heap size)
> Comments/rants/etc. welcome...
> ----
> Bye,
> Roland
> --
> __ . . __
> (o.\ \/ /.o) [email protected]
> \__\/\/__/ MPEG specialist, C&&JAVA&&Sun&&Unix programmer
> /O /==\ O\ TEL +49 641 3992797
> (;O/ \/ \O;)
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