The following commit has been merged into the timers/urgent branch of tip: Commit-ID: b91c8c42ffdd5c983923edb38b3c3e112bfe6263 Gitweb: https://git.kernel.org/tip/b91c8c42ffdd5c983923edb38b3c3e112bfe6263 Author: Christophe Leroy <christophe.le...@c-s.fr> AuthorDate: Tue, 28 Apr 2020 13:16:53 Committer: Thomas Gleixner <t...@linutronix.de> CommitterDate: Wed, 03 Jun 2020 20:50:57 +02:00
lib/vdso: Force inlining of __cvdso_clock_gettime_common() When adding gettime64() to a 32 bit architecture (namely powerpc/32) it has been noticed that GCC doesn't inline anymore __cvdso_clock_gettime_common() because it is called twice (Once by __cvdso_clock_gettime() and once by __cvdso_clock_gettime32). This has the effect of seriously degrading the performance: Before the implementation of gettime64(), gettime() runs in: clock-gettime-monotonic-raw: vdso: 1003 nsec/call clock-gettime-monotonic-coarse: vdso: 592 nsec/call clock-gettime-monotonic: vdso: 942 nsec/call When adding a gettime64() entry point, the standard gettime() performance is degraded by 30% to 50%: clock-gettime-monotonic-raw: vdso: 1300 nsec/call clock-gettime-monotonic-coarse: vdso: 900 nsec/call clock-gettime-monotonic: vdso: 1232 nsec/call Adding __always_inline() to __cvdso_clock_gettime_common() regains the original performance. In terms of code size, the inlining increases the code size by only 176 bytes. This is in the noise for a kernel image. Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Link: https://lkml.kernel.org/r/1ab6a62c356c3bec35d1623563ef9c636205bcda.1588079622.git.christophe.le...@c-s.fr --- lib/vdso/gettimeofday.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index a2909af..7938d3c 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -210,7 +210,7 @@ static __always_inline int do_coarse(const struct vdso_data *vd, clockid_t clk, return 0; } -static __maybe_unused int +static __always_inline int __cvdso_clock_gettime_common(const struct vdso_data *vd, clockid_t clock, struct __kernel_timespec *ts) {
