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Groups > linux.kernel > #1283008
| From | Vineet Gupta <Vineet.Gupta1@synopsys.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [RFC 00/17] ARC Dwarf unwinder improvements |
| Date | 2015-12-03 13:50 +0100 |
| Message-ID | <qBBuF-53y-3@gated-at.bofh.it> (permalink) |
| Organization | linux.* mail to news gateway |
Hi guys, In light of perf -g stalling (as unwinder was taking ~3million cycles for non existent entries), I've revamped the dwarf unwinder. There are some optim tweaks and much of it is "De-generalization" for things which we can safely assume on ARC. Crude Instrumentation shows following improvements per unwinder call: - Avg time come down from ~4650 cycles to ~2794 cycles (+40%) - Max time come down 9793 cycles to 5987 cycles This is on a SMP FPGA config @ 75 MHz It seems much of time (65%) is taken for binary lookup thru ~12k FDE entries, roughly 13 lookups, each likely a dcache miss. git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc # topic-unwinder-rework-4-instrument -Vineet Vineet Gupta (17): ARC: dw2 unwind: Elide generation of const propagated clones ARC: dw2 unwind: remove unused cruft ARC: dw2 unwind: Remove handling of for signal frame ARC: dw2 unwind: Remove FP based unwinding ARC: dw2 unwind: Better printing ARC: dw2 unwind: Don't verify Main FDE Table size everytime ARC: dw2 unwind: Refactor the FDE lookup table (eh_frame_header) code ARC: dw2 unwind: Don't verify FDE lookup table metadata ARC: dw2 unwind: Use striaght forward code to implement binary lookup ARC: dw2 unwind: CIE parsing/validation done only once at startup ARC: dw2 unwind: Elide REG_INVALID check ARC: dw2 unwind: Elide a loop if DW_CFA_register not present ARC: dw2 unwind: Assume all regs to be unsigned long ARC: dw2 unwind: No need for __get_user ARC: dw2 unwind: Single exit point for instrumentation ARC: dw2 unwind: skip regs not updated xxx: instrument arch/arc/include/asm/unwind.h | 47 +-- arch/arc/kernel/Makefile | 1 + arch/arc/kernel/unwind.c | 806 ++++++++++++++++-------------------------- 3 files changed, 313 insertions(+), 541 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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[RFC 00/17] ARC Dwarf unwinder improvements Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2015-12-03 13:50 +0100 [PATCH 11/17] ARC: dw2 unwind: Elide REG_INVALID check Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2015-12-03 13:50 +0100 [PATCH 13/17] ARC: dw2 unwind: Assume all regs to be unsigned long Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2015-12-03 13:50 +0100 [PATCH 06/17] ARC: dw2 unwind: Don't verify Main FDE Table size everytime Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2015-12-03 13:50 +0100 [PATCH 05/17] ARC: dw2 unwind: Better printing Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2015-12-03 13:50 +0100 [PATCH 01/17] ARC: dw2 unwind: Elide generation of const propagated clones Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2015-12-03 13:50 +0100 [PATCH 03/17] ARC: dw2 unwind: Remove handling of for signal frame Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2015-12-03 13:50 +0100 [PATCH 10/17] ARC: dw2 unwind: CIE parsing/validation done only once at startup Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2015-12-03 13:50 +0100 [PATCH 08/17] ARC: dw2 unwind: Don't verify FDE lookup table metadata Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2015-12-03 13:50 +0100
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