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With the C VDSO, the performance is slightly lower, but it is worth it as it will ease maintenance and evolution, and also brings clocks that are not supported with the ASM VDSO. On an 8xx at 132 MHz, vdsotest with the ASM VDSO: gettimeofday: vdso: 828 nsec/call clock-getres-realtime-coarse: vdso: 391 nsec/call clock-gettime-realtime-coarse: vdso: 614 nsec/call clock-getres-realtime: vdso: 460 nsec/call clock-gettime-realtime: vdso: 876 nsec/call clock-getres-monotonic-coarse: vdso: 399 nsec/call clock-gettime-monotonic-coarse: vdso: 691 nsec/call clock-getres-monotonic: vdso: 460 nsec/call clock-gettime-monotonic: vdso: 1026 nsec/call On an 8xx at 132 MHz, vdsotest with the C VDSO: gettimeofday: vdso: 955 nsec/call clock-getres-realtime-coarse: vdso: 545 nsec/call clock-gettime-realtime-coarse: vdso: 592 nsec/call clock-getres-realtime: vdso: 545 nsec/call clock-gettime-realtime: vdso: 941 nsec/call clock-getres-monotonic-coarse: vdso: 545 nsec/call clock-gettime-monotonic-coarse: vdso: 591 nsec/call clock-getres-monotonic: vdso: 545 nsec/call clock-gettime-monotonic: vdso: 940 nsec/call It is even better for gettime with monotonic clocks. Unsupported clocks with ASM VDSO: clock-gettime-boottime: vdso: 3851 nsec/call clock-gettime-tai: vdso: 3852 nsec/call clock-gettime-monotonic-raw: vdso: 3396 nsec/call Same clocks with C VDSO: clock-gettime-tai: vdso: 941 nsec/call clock-gettime-monotonic-raw: vdso: 1001 nsec/call clock-gettime-monotonic-coarse: vdso: 591 nsec/call On an 8321E at 333 MHz, vdsotest with the ASM VDSO: gettimeofday: vdso: 220 nsec/call clock-getres-realtime-coarse: vdso: 102 nsec/call clock-gettime-realtime-coarse: vdso: 178 nsec/call clock-getres-realtime: vdso: 129 nsec/call clock-gettime-realtime: vdso: 235 nsec/call clock-getres-monotonic-coarse: vdso: 105 nsec/call clock-gettime-monotonic-coarse: vdso: 208 nsec/call clock-getres-monotonic: vdso: 129 nsec/call clock-gettime-monotonic: vdso: 274 nsec/call On an 8321E at 333 MHz, vdsotest with the C VDSO: gettimeofday: vdso: 272 nsec/call clock-getres-realtime-coarse: vdso: 160 nsec/call clock-gettime-realtime-coarse: vdso: 184 nsec/call clock-getres-realtime: vdso: 166 nsec/call clock-gettime-realtime: vdso: 281 nsec/call clock-getres-monotonic-coarse: vdso: 160 nsec/call clock-gettime-monotonic-coarse: vdso: 184 nsec/call clock-getres-monotonic: vdso: 169 nsec/call clock-gettime-monotonic: vdso: 275 nsec/call On a Power9 Nimbus DD2.2 at 3.8GHz, with the ASM VDSO: clock-gettime-monotonic: vdso: 35 nsec/call clock-getres-monotonic: vdso: 16 nsec/call clock-gettime-monotonic-coarse: vdso: 18 nsec/call clock-getres-monotonic-coarse: vdso: 522 nsec/call clock-gettime-monotonic-raw: vdso: 598 nsec/call clock-getres-monotonic-raw: vdso: 520 nsec/call clock-gettime-realtime: vdso: 34 nsec/call clock-getres-realtime: vdso: 16 nsec/call clock-gettime-realtime-coarse: vdso: 18 nsec/call clock-getres-realtime-coarse: vdso: 517 nsec/call getcpu: vdso: 8 nsec/call gettimeofday: vdso: 25 nsec/call And with the C VDSO: clock-gettime-monotonic: vdso: 37 nsec/call clock-getres-monotonic: vdso: 20 nsec/call clock-gettime-monotonic-coarse: vdso: 21 nsec/call clock-getres-monotonic-coarse: vdso: 19 nsec/call clock-gettime-monotonic-raw: vdso: 38 nsec/call clock-getres-monotonic-raw: vdso: 20 nsec/call clock-gettime-realtime: vdso: 37 nsec/call clock-getres-realtime: vdso: 20 nsec/call clock-gettime-realtime-coarse: vdso: 20 nsec/call clock-getres-realtime-coarse: vdso: 19 nsec/call getcpu: vdso: 8 nsec/call gettimeofday: vdso: 28 nsec/call Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201126131006.2431205-8-mpe@ellerman.id.au
58 lines
1.3 KiB
ArmAsm
58 lines
1.3 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Userland implementation of gettimeofday() for 64 bits processes in a
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* ppc64 kernel for use in the vDSO
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*
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* Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org),
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* IBM Corp.
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*/
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#include <asm/processor.h>
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#include <asm/ppc_asm.h>
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#include <asm/vdso.h>
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#include <asm/vdso_datapage.h>
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#include <asm/asm-offsets.h>
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#include <asm/unistd.h>
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#include <asm/vdso/gettimeofday.h>
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.text
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/*
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* Exact prototype of gettimeofday
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*
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* int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz);
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*
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*/
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V_FUNCTION_BEGIN(__kernel_gettimeofday)
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cvdso_call __c_kernel_gettimeofday
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V_FUNCTION_END(__kernel_gettimeofday)
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/*
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* Exact prototype of clock_gettime()
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*
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* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp);
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*
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*/
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V_FUNCTION_BEGIN(__kernel_clock_gettime)
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cvdso_call __c_kernel_clock_gettime
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V_FUNCTION_END(__kernel_clock_gettime)
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/*
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* Exact prototype of clock_getres()
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*
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* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res);
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*
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*/
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V_FUNCTION_BEGIN(__kernel_clock_getres)
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cvdso_call __c_kernel_clock_getres
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V_FUNCTION_END(__kernel_clock_getres)
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/*
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* Exact prototype of time()
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*
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* time_t time(time *t);
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*
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*/
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V_FUNCTION_BEGIN(__kernel_time)
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cvdso_call_time __c_kernel_time
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V_FUNCTION_END(__kernel_time)
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