From: Borislav Petkov <bp@suse.de> To: Andy Lutomirski <luto@kernel.org> Cc: x86@kernel.org, Peter Zijlstra <peterz@infradead.org>, John Stultz <john.stultz@linaro.org>, linux-kernel@vger.kernel.org, Len Brown <lenb@kernel.org>, Huang Rui <ray.huang@amd.com>, Denys Vlasenko <dvlasenk@redhat.com>, kvm@vger.kernel.org, Ralf Baechle <ralf@linux-mips.org> Subject: Re: [PATCH v3 03/18] x86/tsc/paravirt: Remove the read_tsc and read_tscp paravirt hooks Date: Fri, 19 Jun 2015 17:32:01 +0200 [thread overview] Message-ID: <20150619153201.GF12979@pd.tnic> (raw) In-Reply-To: <d08a2600fb298af163681e5efd8e599d889a5b97.1434501121.git.luto@kernel.org> On Tue, Jun 16, 2015 at 05:35:51PM -0700, Andy Lutomirski wrote: > We've had read_tsc and read_tscp paravirt hooks since the very > beginning of paravirt, i.e., d3561b7fa0fb ("[PATCH] paravirt: header > and stubs for paravirtualisation"). AFAICT the only paravirt guest > implementation that ever replaced these calls was vmware, and it's > gone. Arguably even vmware shouldn't have hooked rdtsc -- we fully > support systems that don't have a TSC at all, so there's no point > for a paravirt implementation to pretend that we have a TSC but to > replace it. > > I also doubt that these hooks actually worked. Calls to rdtscl and > rdtscll, which respected the hooks, were used seemingly > interchangeably with native_read_tsc, which did not. > > Just remove them. If anyone ever needs them again, they can try > to make a case for why they need them. > > Before, on a paravirt config: > text data bss dec hex filename > 13426505 1827056 14508032 29761593 1c62039 vmlinux > > After: > text data bss dec hex filename > 13426617 1827056 14508032 29761705 1c620a9 vmlinux Those look swapped. I mean, you're removing a bunch of stuff and text grew?! > Signed-off-by: Andy Lutomirski <luto@kernel.org> > --- > arch/x86/include/asm/msr.h | 16 ++++++++-------- > arch/x86/include/asm/paravirt.h | 34 ---------------------------------- > arch/x86/include/asm/paravirt_types.h | 2 -- > arch/x86/kernel/paravirt.c | 2 -- > arch/x86/kernel/paravirt_patch_32.c | 2 -- > arch/x86/xen/enlighten.c | 3 --- > 6 files changed, 8 insertions(+), 51 deletions(-) -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
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From: Borislav Petkov <bp@suse.de> To: Andy Lutomirski <luto@kernel.org> Cc: x86@kernel.org, Peter Zijlstra <peterz@infradead.org>, John Stultz <john.stultz@linaro.org>, linux-kernel@vger.kernel.org, Len Brown <lenb@kernel.org>, Huang Rui <ray.huang@amd.com>, Denys Vlasenko <dvlasenk@redhat.com>, kvm@vger.kernel.org, Ralf Baechle <ralf@linux-mips.org> Subject: Re: [PATCH v3 03/18] x86/tsc/paravirt: Remove the read_tsc and read_tscp paravirt hooks Date: Fri, 19 Jun 2015 17:32:01 +0200 [thread overview] Message-ID: <20150619153201.GF12979@pd.tnic> (raw) In-Reply-To: <d08a2600fb298af163681e5efd8e599d889a5b97.1434501121.git.luto@kernel.org> On Tue, Jun 16, 2015 at 05:35:51PM -0700, Andy Lutomirski wrote: > We've had read_tsc and read_tscp paravirt hooks since the very > beginning of paravirt, i.e., d3561b7fa0fb ("[PATCH] paravirt: header > and stubs for paravirtualisation"). AFAICT the only paravirt guest > implementation that ever replaced these calls was vmware, and it's > gone. Arguably even vmware shouldn't have hooked rdtsc -- we fully > support systems that don't have a TSC at all, so there's no point > for a paravirt implementation to pretend that we have a TSC but to > replace it. > > I also doubt that these hooks actually worked. Calls to rdtscl and > rdtscll, which respected the hooks, were used seemingly > interchangeably with native_read_tsc, which did not. > > Just remove them. If anyone ever needs them again, they can try > to make a case for why they need them. > > Before, on a paravirt config: > text data bss dec hex filename > 13426505 1827056 14508032 29761593 1c62039 vmlinux > > After: > text data bss dec hex filename > 13426617 1827056 14508032 29761705 1c620a9 vmlinux Those look swapped. I mean, you're removing a bunch of stuff and text grew?! > Signed-off-by: Andy Lutomirski <luto@kernel.org> > --- > arch/x86/include/asm/msr.h | 16 ++++++++-------- > arch/x86/include/asm/paravirt.h | 34 ---------------------------------- > arch/x86/include/asm/paravirt_types.h | 2 -- > arch/x86/kernel/paravirt.c | 2 -- > arch/x86/kernel/paravirt_patch_32.c | 2 -- > arch/x86/xen/enlighten.c | 3 --- > 6 files changed, 8 insertions(+), 51 deletions(-) -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- To unsubscribe from this list: send the line "unsubscribe kvm" in
next prev parent reply other threads:[~2015-06-19 15:32 UTC|newest] Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-06-17 0:35 [PATCH v3 00/18] x86/tsc: Clean up rdtsc helpers Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 01/18] x86/tsc: Inline native_read_tsc and remove __native_read_tsc Andy Lutomirski 2015-06-17 9:26 ` Borislav Petkov 2015-07-06 15:39 ` [tip:x86/asm] x86/asm/tsc: Inline native_read_tsc() and remove __native_read_tsc() tip-bot for Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 02/18] x86/msr/kvm: Remove vget_cycles() Andy Lutomirski 2015-06-17 9:42 ` Borislav Petkov 2015-06-17 13:34 ` Paolo Bonzini 2015-07-06 15:40 ` [tip:x86/asm] x86/asm/tsc, kvm: " tip-bot for Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 03/18] x86/tsc/paravirt: Remove the read_tsc and read_tscp paravirt hooks Andy Lutomirski 2015-06-17 9:56 ` Borislav Petkov 2015-06-17 9:56 ` Borislav Petkov 2015-06-19 15:32 ` Borislav Petkov [this message] 2015-06-19 15:32 ` Borislav Petkov 2015-06-19 16:14 ` Andy Lutomirski 2015-06-19 16:14 ` Andy Lutomirski 2015-06-19 17:13 ` Borislav Petkov 2015-06-19 17:13 ` Borislav Petkov 2015-07-06 15:40 ` [tip:x86/asm] x86/asm/tsc, x86/paravirt: Remove read_tsc() and read_tscp() " tip-bot for Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 04/18] x86/tsc: Replace rdtscll with native_read_tsc Andy Lutomirski 2015-06-17 10:03 ` Borislav Petkov 2015-07-06 15:40 ` [tip:x86/asm] x86/asm/tsc: Replace rdtscll() with native_read_tsc () tip-bot for Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 05/18] x86/tsc: Remove the rdtscp and rdtscpll macros Andy Lutomirski 2015-07-06 15:41 ` [tip:x86/asm] x86/asm/tsc: Remove the rdtscp() and rdtscpll() macros tip-bot for Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 06/18] x86/tsc: Use the full 64-bit tsc in tsc_delay Andy Lutomirski 2015-07-06 15:41 ` [tip:x86/asm] x86/asm/tsc: Use the full 64-bit TSC in delay_tsc() tip-bot for Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 07/18] x86/cpu/amd: Use the full 64-bit TSC to detect the 2.6.2 bug Andy Lutomirski 2015-07-06 15:41 ` [tip:x86/asm] x86/asm/tsc, " tip-bot for Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 08/18] baycom_epp: Replace rdtscl() with native_read_tsc() Andy Lutomirski 2015-06-17 0:49 ` Thomas Sailer 2015-06-20 13:54 ` walter harms 2015-06-20 13:54 ` walter harms 2015-06-20 14:14 ` Thomas Gleixner 2015-06-20 14:14 ` Thomas Gleixner 2015-06-20 14:26 ` Andy Lutomirski 2015-06-20 14:26 ` Andy Lutomirski 2015-06-20 16:30 ` Thomas Gleixner 2015-06-20 16:30 ` Thomas Gleixner 2015-07-06 15:42 ` [tip:x86/asm] x86/asm/tsc, drivers/net/hamradio/baycom_epp: " tip-bot for Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 09/18] staging/lirc_serial: Remove TSC-based timing Andy Lutomirski 2015-06-17 0:35 ` Andy Lutomirski 2015-07-06 15:42 ` [tip:x86/asm] x86/asm/tsc, " tip-bot for Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 10/18] input/joystick/analog: Switch from rdtscl() to native_read_tsc() Andy Lutomirski 2015-07-06 15:42 ` [tip:x86/asm] x86/asm/tsc, " tip-bot for Andy Lutomirski 2015-06-17 0:35 ` [PATCH v3 11/18] drivers/input/gameport: Replace rdtscl() with native_read_tsc() Andy Lutomirski 2015-07-06 15:43 ` [tip:x86/asm] x86/asm/tsc, drivers/input/gameport: Replace rdtscl () " tip-bot for Andy Lutomirski 2015-06-17 0:36 ` [PATCH v3 12/18] x86/tsc: Remove rdtscl() Andy Lutomirski 2015-07-06 15:43 ` [tip:x86/asm] x86/asm/tsc: " tip-bot for Andy Lutomirski 2015-06-17 0:36 ` [PATCH v3 13/18] x86/tsc: Rename native_read_tsc() to rdtsc() Andy Lutomirski 2015-06-24 21:38 ` Borislav Petkov 2015-07-06 15:43 ` [tip:x86/asm] x86/asm/tsc: " tip-bot for Andy Lutomirski 2015-06-17 0:36 ` [PATCH v3 14/18] x86: Add rdtsc_ordered() and use it in trivial call sites Andy Lutomirski 2015-07-06 15:44 ` [tip:x86/asm] x86/asm/tsc: " tip-bot for Andy Lutomirski 2015-08-21 7:45 ` [tip:x86/asm] x86/asm/tsc: Add rdtscll() merge helper tip-bot for Ingo Molnar 2015-06-17 0:36 ` [PATCH v3 15/18] x86/tsc: Use rdtsc_ordered() in check_tsc_warp() and drop extra barriers Andy Lutomirski 2015-07-06 15:44 ` [tip:x86/asm] x86/asm/tsc/sync: " tip-bot for Andy Lutomirski 2015-06-17 0:36 ` [PATCH v3 16/18] x86/tsc: In read_tsc, use rdtsc_ordered() instead of get_cycles() Andy Lutomirski 2015-07-06 15:44 ` [tip:x86/asm] x86/asm/tsc: Use rdtsc_ordered() in read_tsc() " tip-bot for Andy Lutomirski 2015-06-17 0:36 ` [PATCH v3 17/18] x86/kvm/tsc: Drop extra barrier and use rdtsc_ordered in kvmclock Andy Lutomirski 2015-06-17 7:47 ` Paolo Bonzini 2015-06-17 13:31 ` Paolo Bonzini 2015-06-20 21:50 ` Borislav Petkov 2015-06-20 21:50 ` Borislav Petkov 2015-07-06 15:45 ` [tip:x86/asm] x86/asm/tsc, x86/kvm: Drop open-coded barrier and use rdtsc_ordered() " tip-bot for Andy Lutomirski 2015-06-17 0:36 ` [PATCH v3 18/18] x86/tsc: Remove rdtsc_barrier() Andy Lutomirski 2015-07-06 15:45 ` [tip:x86/asm] x86/asm/tsc: " tip-bot for Andy Lutomirski 2015-06-17 11:11 ` [PATCH v3 00/18] x86/tsc: Clean up rdtsc helpers Borislav Petkov 2015-06-17 13:37 ` Paolo Bonzini
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