RFC: make UMTX hash table size configurable

[Adrian Chadd]

Hi,

This patch makes the umtx hash table size configurable. It saves ~40k
of footprint from embedded images.

(I can't seem to get phabricator to create a diff based on a set of
files, rather than the whole tree. Sigh.)

***@lucy-11i386:~/work/freebsd/head-embedded/src % svn diff
sys/kern/ sys/conf/options
Index: sys/kern/kern_umtx.c
===================================================================
--- sys/kern/kern_umtx.c (revision 282934)
+++ sys/kern/kern_umtx.c (working copy)
@@ -29,7 +29,7 @@
__FBSDID("$FreeBSD$");

#include "opt_compat.h"
-#include "opt_umtx_profiling.h"
+#include "opt_umtx.h"

#include <sys/param.h>
#include <sys/kernel.h>
@@ -184,7 +184,11 @@
PRI_MAX_TIMESHARE : (td)->td_user_pri)

#define GOLDEN_RATIO_PRIME 2654404609U
+#ifdef UMTX_NUM_CHAINS
+#define UMTX_CHAINS UMTX_NUM_CHAINS
+#else
#define UMTX_CHAINS 512
+#endif /* UMTX_NUM_CHAINS */
#define UMTX_SHIFTS (__WORD_BIT - 9)

#define GET_SHARE(flags) \
Index: sys/conf/options
===================================================================
--- sys/conf/options (revision 282934)
+++ sys/conf/options (working copy)
@@ -209,7 +209,8 @@
SYSVSHM opt_sysvipc.h
SW_WATCHDOG opt_watchdog.h
TURNSTILE_PROFILING
-UMTX_PROFILING
+UMTX_PROFILING opt_umtx.h
+UMTX_NUM_CHAINS opt_umtx.h
VFS_AIO
VERBOSE_SYSINIT
WLCACHE opt_wavelan.h

[Eric van Gyzen]

Adrian,

Good idea. Looks good to me.

Eric

Post by Adrian Chadd
Hi,
This patch makes the umtx hash table size configurable. It saves ~40k
of footprint from embedded images.
(I can't seem to get phabricator to create a diff based on a set of
files, rather than the whole tree. Sigh.)
sys/kern/ sys/conf/options
Index: sys/kern/kern_umtx.c
===================================================================
--- sys/kern/kern_umtx.c (revision 282934)
+++ sys/kern/kern_umtx.c (working copy)
@@ -29,7 +29,7 @@
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
-#include "opt_umtx_profiling.h"
+#include "opt_umtx.h"
#include <sys/param.h>
#include <sys/kernel.h>
@@ -184,7 +184,11 @@
PRI_MAX_TIMESHARE : (td)->td_user_pri)
#define GOLDEN_RATIO_PRIME 2654404609U
+#ifdef UMTX_NUM_CHAINS
+#define UMTX_CHAINS UMTX_NUM_CHAINS
+#else
#define UMTX_CHAINS 512
+#endif /* UMTX_NUM_CHAINS */
#define UMTX_SHIFTS (__WORD_BIT - 9)
#define GET_SHARE(flags) \
Index: sys/conf/options
===================================================================
--- sys/conf/options (revision 282934)
+++ sys/conf/options (working copy)
@@ -209,7 +209,8 @@
SYSVSHM opt_sysvipc.h
SW_WATCHDOG opt_watchdog.h
TURNSTILE_PROFILING
-UMTX_PROFILING
+UMTX_PROFILING opt_umtx.h
+UMTX_NUM_CHAINS opt_umtx.h
VFS_AIO
VERBOSE_SYSINIT
WLCACHE opt_wavelan.h
_______________________________________________
http://lists.freebsd.org/mailman/listinfo/freebsd-arch

[Konstantin Belousov]

Post by Eric van Gyzen
Adrian,
Good idea. Looks good to me.
Eric

Post by Adrian Chadd
Hi,
This patch makes the umtx hash table size configurable. It saves ~40k
of footprint from embedded images.
(I can't seem to get phabricator to create a diff based on a set of
files, rather than the whole tree. Sigh.)
sys/kern/ sys/conf/options
Index: sys/kern/kern_umtx.c
===================================================================
--- sys/kern/kern_umtx.c (revision 282934)
+++ sys/kern/kern_umtx.c (working copy)
@@ -29,7 +29,7 @@
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
-#include "opt_umtx_profiling.h"
+#include "opt_umtx.h"
#include <sys/param.h>
#include <sys/kernel.h>
@@ -184,7 +184,11 @@
PRI_MAX_TIMESHARE : (td)->td_user_pri)
#define GOLDEN_RATIO_PRIME 2654404609U
+#ifdef UMTX_NUM_CHAINS
+#define UMTX_CHAINS UMTX_NUM_CHAINS
+#else
#define UMTX_CHAINS 512
+#endif /* UMTX_NUM_CHAINS */
#define UMTX_SHIFTS (__WORD_BIT - 9)
#define GET_SHARE(flags) \
Index: sys/conf/options
===================================================================
--- sys/conf/options (revision 282934)
+++ sys/conf/options (working copy)
@@ -209,7 +209,8 @@
SYSVSHM opt_sysvipc.h
SW_WATCHDOG opt_watchdog.h
TURNSTILE_PROFILING
-UMTX_PROFILING
+UMTX_PROFILING opt_umtx.h
+UMTX_NUM_CHAINS opt_umtx.h
VFS_AIO
VERBOSE_SYSINIT
WLCACHE opt_wavelan.h

It makes more sense to make the hash size a tunable. The hash mask
would also need to be a variable.