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| author | Laurentiu Tudor <Laurentiu.Tudor@freescale.com> | 2014-05-30 18:59:15 +0400 |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2014-06-21 03:48:34 +0400 |
| commit | 7c48005036a09142a662487ac52000ab845a07e8 (patch) | |
| tree | ad7ac24b26cf1fccdaea1a8772fd89d0ae58632c /arch/powerpc/mm/tlb_low_64e.S | |
| parent | f24bc2701aa3b3c62633046b663ca616ffc3ebe4 (diff) | |
| download | linux-7c48005036a09142a662487ac52000ab845a07e8.tar.xz | |
powerpc/booke64: wrap tlb lock and search in htw miss with FTR_SMT
Virtualized environments may expose a e6500 dual-threaded core
as two single-threaded e6500 cores. Take advantage of this
and get rid of the tlb lock and the trap-causing tlbsx in
the htw miss handler by guarding with CPU_FTR_SMT, as it's
already being done in the bolted tlb1 miss handler.
As seen in the results below, measurements done with lmbench
random memory access latency test running under Freescale's
Embedded Hypervisor, there is a ~34% improvement.
Memory latencies in nanoseconds - smaller is better
(WARNING - may not be correct, check graphs)
----------------------------------------------------
Host Mhz L1 $ L2 $ Main mem Rand mem
--------- --- ---- ---- -------- --------
smt 1665 1.8020 13.2 83.0 1149.7
nosmt 1665 1.8020 13.2 83.0 758.1
Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Cc: Scott Wood <scottwood@freescale.com>
[scottwood@freescale.com: commit message tweak]
Signed-off-by: Scott Wood <scottwood@freescale.com>
Diffstat (limited to 'arch/powerpc/mm/tlb_low_64e.S')
| -rw-r--r-- | arch/powerpc/mm/tlb_low_64e.S | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/powerpc/mm/tlb_low_64e.S b/arch/powerpc/mm/tlb_low_64e.S index 131f1f412bdd..57c4d662be33 100644 --- a/arch/powerpc/mm/tlb_low_64e.S +++ b/arch/powerpc/mm/tlb_low_64e.S @@ -299,6 +299,7 @@ itlb_miss_fault_bolted: * r10 = crap (free to use) */ tlb_miss_common_e6500: +BEGIN_FTR_SECTION /* * Search if we already have an indirect entry for that virtual * address, and if we do, bail out. @@ -333,6 +334,7 @@ tlb_miss_common_e6500: andis. r10,r10,MAS1_VALID@h bne tlb_miss_done_e6500 +END_FTR_SECTION_IFSET(CPU_FTR_SMT) /* Now, we need to walk the page tables. First check if we are in * range. @@ -393,11 +395,13 @@ tlb_miss_common_e6500: tlb_miss_done_e6500: .macro tlb_unlock_e6500 +BEGIN_FTR_SECTION beq cr1,1f /* no unlock if lock was recursively grabbed */ li r15,0 isync stb r15,0(r11) 1: +END_FTR_SECTION_IFSET(CPU_FTR_SMT) .endm tlb_unlock_e6500 |