From: Giovanni Gherdovich <ggherdovich@suse.cz>
To: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@suse.de>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>
Cc: x86@kernel.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
Giovanni Gherdovich <ggherdovich@suse.cz>
Subject: [PATCH v2 0/3] More frequency invariance fixes for x86
Date: Sun, 31 May 2020 20:24:50 +0200 [thread overview]
Message-ID: <20200531182453.15254-1-ggherdovich@suse.cz> (raw)
v1 at https://lore.kernel.org/lkml/20200428132450.24901-1-ggherdovich@suse.cz/
changes wrt v1:
- add Peter Zijlstra's code to check for multiplication overflow, see
https://lore.kernel.org/lkml/20200501133042.GE3762@hirez.programming.kicks-ass.net/
- put all frequence invariant code behind CONFIG_X86_64, as the overflow
checks need 64 bits operations, see the build error at
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org/thread/7GDIBOMNVDG5W2XZD4EICE2TUZR3THBN/
- add additional patch to check for when base_freq > turbo_freq,
suggested by Peter Zijlstra at
https://lore.kernel.org/lkml/20200501130427.GD3762@hirez.programming.kicks-ass.net/
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Cover Letter from v1:
Patch 1/2 prevents a division by zero in case the product
"delta_MPERF * arch_max_freq_ratio" overflows u64, as suggested by Linus at [1].
This patch supersedes the version at [2], as it also disables frequency
invariance when that overflow happens.
Patch 2/2 implements the recommendation by Ricardo Neri to check for an all
zero MSR_TURBO_RATIO_LIMIT and disable freq invariance in that case too.
[1] https://lore.kernel.org/lkml/CAHk-=wiX+NT2yxtdPszH9U_S96MCNQA56GJFXY45mZc47yG5KQ@mail.gmail.com/
[2] https://lore.kernel.org/lkml/20200422144055.18171-1-ggherdovich@suse.cz/
[3] https://lore.kernel.org/lkml/20200424013222.GA26355@ranerica-svr.sc.intel.com/
Giovanni Gherdovich (3):
x86, sched: check for counters overflow in frequency invariant
accounting
x86, sched: Bail out of frequency invariance if turbo frequency is
unknown
x86, sched: Bail out of frequency invariance if turbo_freq/base_freq
gives 0
arch/x86/include/asm/topology.h | 2 +-
arch/x86/kernel/smpboot.c | 50 +++++++++++++++++++++++++++++++++--------
2 files changed, 42 insertions(+), 10 deletions(-)
--
2.16.4
next reply other threads:[~2020-05-31 18:26 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-31 18:24 Giovanni Gherdovich [this message]
2020-05-31 18:24 ` [PATCH v2 1/3] x86, sched: check for counters overflow in frequency invariant accounting Giovanni Gherdovich
2020-06-03 14:22 ` Rafael J. Wysocki
2020-06-16 12:21 ` [tip: sched/core] " tip-bot2 for Giovanni Gherdovich
2020-10-22 8:46 ` [PATCH v2 1/3] " Peter Zijlstra
2020-10-22 12:21 ` Giovanni Gherdovich
2020-10-22 12:30 ` Peter Zijlstra
2020-05-31 18:24 ` [PATCH v2 2/3] x86, sched: Bail out of frequency invariance if turbo frequency is unknown Giovanni Gherdovich
2020-06-01 23:34 ` Ricardo Neri
2020-07-06 20:19 ` Ira Weiny
2020-06-03 14:23 ` Rafael J. Wysocki
2020-06-16 12:21 ` [tip: sched/core] " tip-bot2 for Giovanni Gherdovich
2020-05-31 18:24 ` [PATCH v2 3/3] x86, sched: Bail out of frequency invariance if turbo_freq/base_freq gives 0 Giovanni Gherdovich
2020-06-03 14:51 ` Rafael J. Wysocki
2020-06-16 12:21 ` [tip: sched/core] " tip-bot2 for Giovanni Gherdovich
2020-06-03 12:31 ` [PATCH v2 0/3] More frequency invariance fixes for x86 Peter Zijlstra
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