From: Michael Ellerman <patch-notifications@ellerman•id.au>
To: Nicholas Piggin <npiggin@gmail•com>, linuxppc-dev@lists•ozlabs.org
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux•vnet.ibm.com>,
Nicholas Piggin <npiggin@gmail•com>
Subject: Re: [v2, 7/7] powerpc/64s/radix: Improve TLB flushing for page table freeing
Date: Tue, 14 Nov 2017 22:12:19 +1100 (AEDT) [thread overview]
Message-ID: <3yblGC6FSSz9sPs@ozlabs.org> (raw)
In-Reply-To: <20171107075309.20500-8-npiggin@gmail.com>
On Tue, 2017-11-07 at 07:53:09 UTC, Nicholas Piggin wrote:
> Unmaps that free page tables always flush the entire PID, which is
> sub-optimal. Provide TLB range flushing with an additional PWC flush
> that can be use for va range invalidations with PWC flush.
>
> Time to munmap N pages of memory including last level page table
> teardown (after mmap, touch), local invalidate:
> N 1 2 4 8 16 32 64
> vanilla 3.2us 3.3us 3.4us 3.6us 4.1us 5.2us 7.2us
> patched 1.4us 1.5us 1.7us 1.9us 2.6us 3.7us 6.2us
>
> Global invalidate:
> N 1 2 4 8 16 32 64
> vanilla 2.2us 2.3us 2.4us 2.6us 3.2us 4.1us 6.2us
> patched 2.1us 2.5us 3.4us 5.2us 8.7us 15.7us 6.2us
>
> Local invalidates get much better across the board. Global ones have
> the same issue where multiple tlbies for va flush do get slower than
> the single tlbie to invalidate the PID. None of this test captures
> the TLB benefits of avoiding killing everything.
>
> Global gets worse, but it is brought in to line with global invalidate
> for munmap()s that do not free page tables.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/0b2f5a8a792755c88bd786f89712a9
cheers
prev parent reply other threads:[~2017-11-14 11:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-07 7:53 [PATCH v2 0/7] powerpc/64s/radix TLB flush fixes and performance improvements Nicholas Piggin
2017-11-07 7:53 ` [PATCH v2 1/7] powerpc/64s/radix: tlbie improve preempt handling Nicholas Piggin
2017-11-07 7:53 ` [PATCH v2 2/7] powerpc/64s/radix: Fix process table entry cache invalidation Nicholas Piggin
2017-11-07 7:53 ` [PATCH v2 3/7] powerpc/64s/radix: optimize TLB range flush barriers Nicholas Piggin
2017-11-14 11:12 ` [v2,3/7] " Michael Ellerman
2017-11-07 7:53 ` [PATCH v2 4/7] powerpc/64s/radix: Implement _tlbie(l)_va_range flush functions Nicholas Piggin
2017-11-14 11:12 ` [v2, " Michael Ellerman
2017-11-07 7:53 ` [PATCH v2 5/7] powerpc/64s/radix: Optimize flush_tlb_range Nicholas Piggin
2017-11-14 11:12 ` [v2,5/7] " Michael Ellerman
2017-11-07 7:53 ` [PATCH v2 6/7] powerpc/64s/radix: Introduce local single page ceiling for TLB range flush Nicholas Piggin
2017-11-14 11:12 ` [v2, " Michael Ellerman
2017-11-07 7:53 ` [PATCH v2 7/7] powerpc/64s/radix: Improve TLB flushing for page table freeing Nicholas Piggin
2017-11-14 11:12 ` Michael Ellerman [this message]
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