[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <ZtnkZsHJESAqU-FH@zx2c4.com>
Date: Thu, 5 Sep 2024 19:03:34 +0200
From: "Jason A. Donenfeld" <Jason@...c4.com>
To: Christophe Leroy <christophe.leroy@...roup.eu>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Steven Rostedt <rostedt@...dmis.org>,
Masami Hiramatsu <mhiramat@...nel.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
Naveen N Rao <naveen@...nel.org>,
Nathan Chancellor <nathan@...nel.org>,
Nick Desaulniers <ndesaulniers@...gle.com>,
Bill Wendling <morbo@...gle.com>,
Justin Stitt <justinstitt@...gle.com>,
Shuah Khan <shuah@...nel.org>, linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, linux-kselftest@...r.kernel.org,
llvm@...ts.linux.dev, linux-fsdevel@...r.kernel.org,
linux-mm@...ck.org, linux-trace-kernel@...r.kernel.org,
Adhemerval Zanella <adhemerval.zanella@...aro.org>,
Xi Ruoyao <xry111@...111.site>
Subject: Re: [PATCH v5 4/5] powerpc/vdso: Wire up getrandom() vDSO
implementation on VDSO32
On Thu, Sep 05, 2024 at 06:55:27PM +0200, Christophe Leroy wrote:
>
>
> Le 05/09/2024 à 18:13, Jason A. Donenfeld a écrit :
> >> +/*
> >> + * The macro sets two stack frames, one for the caller and one for the callee
> >> + * because there are no requirement for the caller to set a stack frame when
> >> + * calling VDSO so it may have omitted to set one, especially on PPC64
> >> + */
> >> +
> >> +.macro cvdso_call funct
> >> + .cfi_startproc
> >> + PPC_STLU r1, -PPC_MIN_STKFRM(r1)
> >> + .cfi_adjust_cfa_offset PPC_MIN_STKFRM
> >> + mflr r0
> >> + PPC_STLU r1, -PPC_MIN_STKFRM(r1)
> >> + .cfi_adjust_cfa_offset PPC_MIN_STKFRM
> >> + PPC_STL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
> >> + .cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF
> >> + get_datapage r8
> >> + addi r8, r8, VDSO_RNG_DATA_OFFSET
> >> + bl CFUNC(DOTSYM(\funct))
> >> + PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
> >> + cmpwi r3, 0
> >> + mtlr r0
> >> + addi r1, r1, 2 * PPC_MIN_STKFRM
> >> + .cfi_restore lr
> >> + .cfi_def_cfa_offset 0
> >> + crclr so
> >> + bgelr+
> >> + crset so
> >> + neg r3, r3
> >> + blr
> >> + .cfi_endproc
> >> +.endm
> >
> > You wrote in an earlier email that this worked with time namespaces, but
> > in my testing that doesn't seem to be the case.
>
> Did I write that ? I can't remember and neither can I remember testing
> it with time namespaces.
It's possible I confused you with someone else? Hum. Anyway...
> > From my test harness [1]:
> >
> > Normal single thread
> > vdso: 25000000 times in 12.494133131 seconds
> > libc: 25000000 times in 69.594625188 seconds
> > syscall: 25000000 times in 67.349243972 seconds
> > Time namespace single thread
> > vdso: 25000000 times in 71.673057436 seconds
> > libc: 25000000 times in 71.712774121 seconds
> > syscall: 25000000 times in 66.902318080 seconds
> >
> > I'm seeing this on ppc, ppc64, and ppc64le.
>
> What is the command to use to test with time namespace ?
Look at the C in the commit I linked.
Powered by blists - more mailing lists