From: Adhemerval Zanella <azanella@linux•vnet.ibm.com>
To: linuxppc-dev@lists•ozlabs.org
Subject: [PATCH] [RFC] powerpc: Add VDSO version of time
Date: Tue, 19 Mar 2013 16:55:31 -0300 [thread overview]
Message-ID: <5148C2B3.6010408@linux.vnet.ibm.com> (raw)
Hi all,
This patch implement the time syscall as vDSO. I have a glibc patch
to use it as IFUNC (as latest gettimeofday patch). Below the perf
numbers:
Baseline PPC32: 380 nsec
Baseline PPC64: 352 nsec
vdso PPC32: 20 nsec
vdso PPC64: 20 nsec
I focused on 64 bit kernel, do I need to provide a scheme for 32 bits
as well?
Any tips, advices, comments?
--
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 1b2076f..d4f463a 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -113,6 +113,10 @@ static struct vdso_patch_def vdso_patches[] = {
CPU_FTR_USE_TB, 0,
"__kernel_get_tbfreq", NULL
},
+ {
+ CPU_FTR_USE_TB, 0,
+ "__kernel_time", NULL
+ },
};
/*
diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
index 4ee09ee..9a60a87 100644
--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
@@ -181,6 +181,35 @@ V_FUNCTION_END(__kernel_clock_getres)
/*
+ * Exact prototype of time()
+ *
+ * time_t time(time *t);
+ *
+ */
+V_FUNCTION_BEGIN(__kernel_time)
+ .cfi_startproc
+ mflr r12
+ .cfi_register lr,r12
+
+ mr r11,r3 /* r11 holds t */
+ bl __get_datapage@local
+ mr r9, r3 /* datapage ptr in r9 */
+
+1: lwz r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
+ lwz r3,STAMP_XTIME+TSPEC_TV_SEC(r9)
+ andi. r0,r8,1 /* pending update ? loop */
+ bne- 1b
+
+ cmplwi r11,0 /* check if t is NULL */
+ beq 2f
+ stw r3,0(r11) /* store result at *t */
+2: mtlr r12
+ crclr cr0*4+so
+ blr
+ .cfi_endproc
+V_FUNCTION_END(__kernel_time)
+
+/*
* This is the core of clock_gettime() and gettimeofday(),
* it returns the current time in r3 (seconds) and r4.
* On entry, r7 gives the resolution of r4, either USEC_PER_SEC
diff --git a/arch/powerpc/kernel/vdso32/vdso32.lds.S b/arch/powerpc/kernel/vdso32/vdso32.lds.S
index 43200ba..f223409 100644
--- a/arch/powerpc/kernel/vdso32/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso32/vdso32.lds.S
@@ -150,6 +150,7 @@ VERSION
#ifdef CONFIG_PPC64
__kernel_getcpu;
#endif
+ __kernel_time;
local: *;
};
diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S
index e97a9a0..f05aa68 100644
--- a/arch/powerpc/kernel/vdso64/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso64/gettimeofday.S
@@ -164,6 +164,35 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
.cfi_endproc
V_FUNCTION_END(__kernel_clock_getres)
+/*
+ * Exact prototype of time()
+ *
+ * time_t time(time *t);
+ *
+ */
+V_FUNCTION_BEGIN(__kernel_time)
+ .cfi_startproc
+ mflr r12
+ .cfi_register lr,r12
+
+ mr r11,r3 /* r11 holds t */
+ bl V_LOCAL_FUNC(__get_datapage)
+
+1: ld r8,CFG_TB_UPDATE_COUNT(r3)
+ ld r4,STAMP_XTIME+TSPC64_TV_SEC(r3)
+ andi. r0,r8,1 /* pending update ? loop */
+ bne- 1b
+
+ cmpldi r11,0 /* check if t is NULL */
+ beq 2f
+ std r4,0(r11) /* store result at *t */
+2: mtlr r12
+ crclr cr0*4+so
+ mr r3,r4
+ blr
+ .cfi_endproc
+V_FUNCTION_END(__kernel_time)
+
/*
* This is the core of clock_gettime() and gettimeofday(),
diff --git a/arch/powerpc/kernel/vdso64/vdso64.lds.S b/arch/powerpc/kernel/vdso64/vdso64.lds.S
index e6c1758..e486381 100644
--- a/arch/powerpc/kernel/vdso64/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso64/vdso64.lds.S
@@ -147,6 +147,7 @@ VERSION
__kernel_sync_dicache_p5;
__kernel_sigtramp_rt64;
__kernel_getcpu;
+ __kernel_time;
local: *;
};
next reply other threads:[~2013-03-19 19:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-19 19:55 Adhemerval Zanella [this message]
2013-03-20 5:00 ` [PATCH] [RFC] powerpc: Add VDSO version of time Benjamin Herrenschmidt
2013-03-21 13:40 ` Adhemerval Zanella
2013-03-26 17:32 ` Adhemerval Zanella
2013-04-04 19:22 ` Adhemerval Zanella
2013-04-05 6:21 ` Michael Ellerman
2013-04-05 18:49 ` Adhemerval Zanella
2013-04-08 14:05 ` Adhemerval Zanella
2013-04-18 5:58 ` Michael Ellerman
2013-04-18 22:38 ` Anton Blanchard
2013-04-22 19:29 ` Adhemerval Zanella
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