Messages in this thread | | | From | Lv Zheng <> | Subject | [PATCH 0/6] ACPI/OSL: Rework of ACPICA memory OSLs to improve performance. | Date | Thu, 23 Oct 2014 10:11:57 +0800 |
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It is reported that there is a performance issue in the ACPICA OSL implementation around memory mappings.
On the reported platforms, there is a debugging facility implemented in the ACPI namespace using circular logging buffer: Name (DPTR, 0x3AFEB000) Name (EPTR, 0x3AFFB000) Name (CPTR, 0x3AFEB010) Mutex (MMUT, 0x00) Method (MDBG, 1, Serialized) { Store (Acquire (MMUT, 0x03E8), Local0) If (Local0 == Zero) { OperationRegion (ABLK, SystemMemory, CPTR, 0x10) Field (ABLK, ByteAcc, NoLock, Preserve) { AAAA, 128 } Store (Arg0, AAAA) /* \MDBG.AAAA */ CPTR = (CPTR + 0x10) /* \CPTR */ If (CPTR >= EPTR) { CPTR = (DPTR + 0x10) /* \CPTR */ } Release (MMUT) } Return (Local0) } This function is heavily invoked by other ACPI control methods. The reported platforms suffer from 2-5 minutes kernel stuck in the end of accessing the mapped circular buffer system memory region. By instrumentation, the 2-5 minutes time consumption overhead can be seen to happen on the synchronize_rcu() invoked in the acpi_os_unmap_memory().
This patchset removes the synchronize_rcu() from the hot path to improve the performance.
Lv Zheng (6): ACPI/OSL: Split memory operation region implementations to a seperate file. ACPI/OSL: Rename system memory functions. ACPI/OSL: Cleanup memory access functions by merging duplicate code. ACPI/OSL: Add acpi_map2virt() to merge duplicate code. ACPI/OSL: Cleanup branch logics. ACPI/OSL: Fix performance issue in system memory lockings.
drivers/acpi/Makefile | 2 +- drivers/acpi/mem.c | 414 +++++++++++++++++++++++++++++++++++++++++++++++++ drivers/acpi/osl.c | 381 --------------------------------------------- 3 files changed, 415 insertions(+), 382 deletions(-) create mode 100644 drivers/acpi/mem.c
-- 1.7.10
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