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2019-05-22tcg: Add support for vector compare selectRichard Henderson
Perform a per-element conditional move. This combination operation is easier to implement on some host vector units than plain cmp+bitsel. Omit the usual gvec interface, as this is intended to be used by target-specific gvec expansion call-backs. Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-05-22tcg: Add support for vector bitwise selectRichard Henderson
This operation performs d = (b & a) | (c & ~a), and is present on a majority of host vector units. Include gvec expanders. Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-05-13tcg: Add support for vector absolute valueRichard Henderson
Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-05-13tcg: Specify optional vector requirements with a listRichard Henderson
Replace the single opcode in .opc with a null-terminated array in .opt_opc. We still require that all opcodes be used with the same .vece. Validate the contents of this list with CONFIG_DEBUG_TCG. All tcg_gen_*_vec functions will check any list active during .fniv expansion. Swap the active list in and out as we expand other opcodes, or take control away from the front-end function. Convert all existing vector aware front ends. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-04-24tcg: Restart TB generation after relocation overflowRichard Henderson
If the TB generates too much code, such that backend relocations overflow, try again with a smaller TB. In support of this, move relocation processing from a random place within tcg_out_op, in the handling of branch opcodes, to a new function at the end of tcg_gen_code. This is not a complete solution, as there are additional relocs generated for out-of-line ldst handling and constant pools. Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-04-24tcg: Add INDEX_op_extract2_{i32,i64}Richard Henderson
This will let backends implement the double-word shift operation. Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-04-18tcg: Simplify how dump_exec_info() printsMarkus Armbruster
dump_exec_info() takes an fprintf()-like callback and a FILE * to pass to it. Its only caller hmp_info_jit() passes monitor_fprintf() and the current monitor cast to FILE *. monitor_fprintf() casts it right back, and is otherwise identical to monitor_printf(). The type-punning is ugly. Drop the callback, and call qemu_printf() instead. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20190417191805.28198-5-armbru@redhat.com>
2019-04-18tcg: Simplify how dump_opcount_info() printsMarkus Armbruster
dump_opcount_info() takes an fprintf()-like callback and a FILE * to pass to it. Its only caller hmp_info_opcount() passes monitor_fprintf() and the current monitor cast to FILE *. monitor_fprintf() casts it right back, and is otherwise identical to monitor_printf(). The type-punning is ugly. Drop the callback, and call qemu_printf() instead. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20190417191805.28198-4-armbru@redhat.com>
2019-02-11tcg: Diagnose referenced labels that have not been emittedRichard Henderson
Currently, a jump to a label that is not defined anywhere will be emitted not be relocated. This results in a jump to a random jump target. With tcg debugging, print a diagnostic to the -d op file and abort. This could help debug or detect errors like c2d9644e6d ("target/arm: Fix crash on conditional instruction in an IT block") Reported-by: Roman Kapl <code@rkapl.cz> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-01-28tcg: Add opcodes for vector minmax arithmeticRichard Henderson
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-01-28tcg: Add opcodes for vector saturated arithmeticRichard Henderson
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-01-11qemu/queue.h: simplify reverse access to QTAILQPaolo Bonzini
The new definition of QTAILQ does not require passing the headname, remove it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-01-11qemu/queue.h: leave head structs anonymous unless necessaryPaolo Bonzini
Most list head structs need not be given a name. In most cases the name is given just in case one is going to use QTAILQ_LAST, QTAILQ_PREV or reverse iteration, but this does not apply to lists of other kinds, and even for QTAILQ in practice this is only rarely needed. In addition, we will soon reimplement those macros completely so that they do not need a name for the head struct. So clean up everything, not giving a name except in the rare case where it is necessary. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-12-26tcg: Add TCG_OPF_BB_EXITRichard Henderson
Use this to notice the opcodes that exit the TB, which implies that local temps are really dead and need not be synced. Previously we so marked the true end of the TB, but that was immediately overwritten by the la_bb_end invoked by any TCG_OPF_BB_END opcode, like exit_tb. Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-12-26tcg: Dump register preference info with livenessRichard Henderson
Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-12-26tcg: Add output_pref to TCGOpRichard Henderson
Allocate storage for, but do not yet fill in, per-opcode preferences for the output operands. Pass it in to the register allocation routines for output operands. Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-12-26tcg: Reference count labelsRichard Henderson
Increment when adding branches, and decrement when removing them. Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-12-26tcg: Add TCG_CALL_NO_RETURNRichard Henderson
Remember which helpers have been marked noreturn. Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-12-26tcg: Renumber TCG_CALL_* flagsRichard Henderson
Previously, the low 4 bits were used for TCG_CALL_TYPE_MASK, which was removed in 6a18ae2d2947532d5c26439548afa0481c4529f9. Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-12-17tcg: Drop nargs from tcg_op_insert_{before,after}Emilio G. Cota
It's unused since 75e8b9b7aa0b95a761b9add7e2f09248b101a392. Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20181209193749.12277-9-cota@braap.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-12-12tcg/tcg.h: Remove GCC check for tcg_debug_assert() macroThomas Huth
Both GCC v4.8 and Clang v3.4 (our minimum versions) support __builtin_unreachable(), so we can remove the version check here now. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Thomas Huth <thuth@redhat.com>
2018-10-18tcg: Split CONFIG_ATOMIC128Richard Henderson
GCC7+ will no longer advertise support for 16-byte __atomic operations if only cmpxchg is supported, as for x86_64. Fortunately, x86_64 still has support for __sync_compare_and_swap_16 and we can make use of that. AArch64 does not have, nor ever has had such support, so open-code it. Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-18tcg: distribute tcg_time into TCG contextsEmilio G. Cota
When we implemented per-vCPU TCG contexts, we forgot to also distribute the tcg_time counter, which has remained as a global accessed without any serialization, leading to potentially missed counts. Fix it by distributing the field over the TCG contexts, embedding it into TCGProfile with a field called "cpu_exec_time", which is more descriptive than "tcg_time". Add a function to query this value directly, and for completeness, fill in the field in tcg_profile_snapshot, even though its callers do not use it. Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20181010144853.13005-5-cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-18tcg: plug holes in struct TCGProfileEmilio G. Cota
This plugs two 4-byte holes in 64-bit. Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20181010144853.13005-4-cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-06-15tcg: Reduce max TB opcode countRichard Henderson
Also, assert that we don't overflow any of two different offsets into the TB. Both unwind and goto_tb both record a uint16_t for later use. This fixes an arm-softmmu test case utilizing NEON in which there is a TB generated that runs to 7800 opcodes, and compiles to 96k on an x86_64 host. This overflows the 16-bit offset in which we record the goto_tb reset offset. Because of that overflow, we install a jump destination that goes to neverland. Boom. With this reduced op count, the same TB compiles to about 48k for aarch64, ppc64le, and x86_64 hosts, and neither assertion fires. Cc: qemu-stable@nongnu.org Reported-by: "Jason A. Donenfeld" <Jason@zx2c4.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-06-15tcg: remove tb_lockEmilio G. Cota
Use mmap_lock in user-mode to protect TCG state and the page descriptors. In !user-mode, each vCPU has its own TCG state, so no locks needed. Per-page locks are used to protect the page descriptors. Per-TB locks are used in both modes to protect TB jumps. Some notes: - tb_lock is removed from notdirty_mem_write by passing a locked page_collection to tb_invalidate_phys_page_fast. - tcg_tb_lookup/remove/insert/etc have their own internal lock(s), so there is no need to further serialize access to them. - do_tb_flush is run in a safe async context, meaning no other vCPU threads are running. Therefore acquiring mmap_lock there is just to please tools such as thread sanitizer. - Not visible in the diff, but tb_invalidate_phys_page already has an assert_memory_lock. - cpu_io_recompile is !user-only, so no mmap_lock there. - Added mmap_unlock()'s before all siglongjmp's that could be called in user-mode while mmap_lock is held. + Added an assert for !have_mmap_lock() after returning from the longjmp in cpu_exec, just like we do in cpu_exec_step_atomic. Performance numbers before/after: Host: AMD Opteron(tm) Processor 6376 ubuntu 17.04 ppc64 bootup+shutdown time 700 +-+--+----+------+------------+-----------+------------*--+-+ | + + + + + *B | | before ***B*** ** * | |tb lock removal ###D### *** | 600 +-+ *** +-+ | ** # | | *B* #D | | *** * ## | 500 +-+ *** ### +-+ | * *** ### | | *B* # ## | | ** * #D# | 400 +-+ ** ## +-+ | ** ### | | ** ## | | ** # ## | 300 +-+ * B* #D# +-+ | B *** ### | | * ** #### | | * *** ### | 200 +-+ B *B #D# +-+ | #B* * ## # | | #* ## | | + D##D# + + + + | 100 +-+--+----+------+------------+-----------+------------+--+-+ 1 8 16 Guest CPUs 48 64 png: https://imgur.com/HwmBHXe debian jessie aarch64 bootup+shutdown time 90 +-+--+-----+-----+------------+------------+------------+--+-+ | + + + + + + | | before ***B*** B | 80 +tb lock removal ###D### **D +-+ | **### | | **## | 70 +-+ ** # +-+ | ** ## | | ** # | 60 +-+ *B ## +-+ | ** ## | | *** #D | 50 +-+ *** ## +-+ | * ** ### | | **B* ### | 40 +-+ **** # ## +-+ | **** #D# | | ***B** ### | 30 +-+ B***B** #### +-+ | B * * # ### | | B ###D# | 20 +-+ D ##D## +-+ | D# | | + + + + + + | 10 +-+--+-----+-----+------------+------------+------------+--+-+ 1 8 16 Guest CPUs 48 64 png: https://imgur.com/iGpGFtv The gains are high for 4-8 CPUs. Beyond that point, however, unrelated lock contention significantly hurts scalability. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-06-15tcg: move tb_ctx.tb_phys_invalidate_count to tcg_ctxEmilio G. Cota
Thereby making it per-TCGContext. Once we remove tb_lock, this will avoid an atomic increment every time a TB is invalidated. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-06-15tcg: track TBs with per-region BST'sEmilio G. Cota
This paves the way for enabling scalable parallel generation of TCG code. Instead of tracking TBs with a single binary search tree (BST), use a BST for each TCG region, protecting it with a lock. This is as scalable as it gets, since each TCG thread operates on a separate region. The core of this change is the introduction of struct tcg_region_tree, which contains a pointer to a GTree and an associated lock to serialize accesses to it. We then allocate an array of tcg_region_tree's, adding the appropriate padding to avoid false sharing based on qemu_dcache_linesize. Given a tc_ptr, we first find the corresponding region_tree. This is done by special-casing the first and last regions first, since they might be of size != region.size; otherwise we just divide the offset by region.stride. I was worried about this division (several dozen cycles of latency), but profiling shows that this is not a fast path. Note that region.stride is not required to be a power of two; it is only required to be a multiple of the host's page size. Note that with this design we can also provide consistent snapshots about all region trees at once; for instance, tcg_tb_foreach acquires/releases all region_tree locks before/after iterating over them. For this reason we now drop tb_lock in dump_exec_info(). As an alternative I considered implementing a concurrent BST, but this can be tricky to get right, offers no consistent snapshots of the BST, and performance and scalability-wise I don't think it could ever beat having separate GTrees, given that our workload is insert-mostly (all concurrent BST designs I've seen focus, understandably, on making lookups fast, which comes at the expense of convoluted, non-wait-free insertions/removals). Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-06-01tcg: Pass tb and index to tcg_gen_exit_tb separatelyRichard Henderson
Do the cast to uintptr_t within the helper, so that the compiler can type check the pointer argument. We can also do some more sanity checking of the index argument. Reviewed-by: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-11Merge remote-tracking branch ↵Peter Maydell
'remotes/pmaydell/tags/pull-target-arm-20180510' into staging target-arm queue: * hw/arm/iotkit.c: fix minor memory leak * softfloat: fix wrong-exception-flags bug for multiply-add corner case * arm: isolate and clean up DTB generation * implement Arm v8.1-Atomics extension * Fix some bugs and missing instructions in the v8.2-FP16 extension # gpg: Signature made Thu 10 May 2018 18:44:34 BST # gpg: using RSA key 3C2525ED14360CDE # gpg: Good signature from "Peter Maydell <peter.maydell@linaro.org>" # gpg: aka "Peter Maydell <pmaydell@gmail.com>" # gpg: aka "Peter Maydell <pmaydell@chiark.greenend.org.uk>" # Primary key fingerprint: E1A5 C593 CD41 9DE2 8E83 15CF 3C25 25ED 1436 0CDE * remotes/pmaydell/tags/pull-target-arm-20180510: (21 commits) target/arm: Clear SVE high bits for FMOV target/arm: Fix float16 to/from int16 target/arm: Implement vector shifted FCVT for fp16 target/arm: Implement vector shifted SCVF/UCVF for fp16 target/arm: Enable ARM_FEATURE_V8_ATOMICS for user-only target/arm: Implement CAS and CASP target/arm: Fill in disas_ldst_atomic target/arm: Introduce ARM_FEATURE_V8_ATOMICS and initial decode target/riscv: Use new atomic min/max expanders tcg: Use GEN_ATOMIC_HELPER_FN for opposite endian atomic add tcg: Introduce atomic helpers for integer min/max target/xtensa: Use new min/max expanders target/arm: Use new min/max expanders tcg: Introduce helpers for integer min/max atomic.h: Work around gcc spurious "unused value" warning make sure that we aren't overwriting mc->get_hotplug_handler by accident arm/boot: split load_dtb() from arm_load_kernel() platform-bus-device: use device plug callback instead of machine_done notifier pc: simplify MachineClass::get_hotplug_handler handling softfloat: Handle default NaN mode after pickNaNMulAdd, not before ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org> # Conflicts: # target/riscv/translate.c
2018-05-10tcg: Introduce atomic helpers for integer min/maxRichard Henderson
Given that this atomic operation will be used by both risc-v and aarch64, let's not duplicate code across the two targets. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180508151437.4232-5-richard.henderson@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-05-09tcg: Limit the number of ops in a TBRichard Henderson
In 6001f7729e12 we partially attempt to address the branch displacement overflow caused by 15fa08f845. However, gcc/testsuite/gcc.target/aarch64/advsimd-intrinsics/vqtbX.c is a testcase that contains a TB so large as to overflow anyway. The limit here of 8000 ops produces a maximum output TB size of 24112 bytes on a ppc64le host with that test case. This is still much less than the maximum forward branch distance of 32764 bytes. Cc: qemu-stable@nongnu.org Fixes: 15fa08f845 ("tcg: Dynamically allocate TCGOps") Reviewed-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-01tcg: workaround branch instruction overflow in tcg_out_qemu_ld/stLaurent Vivier
ppc64 uses a BC instruction to call the tcg_out_qemu_ld/st slow path. BC instruction uses a relative address encoded on 14 bits. The slow path functions are added at the end of the generated instructions buffer, in the reverse order of the callers. So more we have slow path functions more the distance between the caller (BC) and the function increases. This patch changes the behavior to generate the functions in the same order of the callers. Cc: qemu-stable@nongnu.org Fixes: 15fa08f845 ("tcg: Dynamically allocate TCGOps") Signed-off-by: Laurent Vivier <lvivier@redhat.com> Message-Id: <20180429235840.16659-1-lvivier@redhat.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-01tcg: Improve TCGv_ptr supportRichard Henderson
Drop TCGV_PTR_TO_NAT and TCGV_NAT_TO_PTR internal macros. Add tcg_temp_local_new_ptr, tcg_gen_brcondi_ptr, tcg_gen_ext_i32_ptr, tcg_gen_trunc_i64_ptr, tcg_gen_extu_ptr_i64, tcg_gen_trunc_ptr_i32. Use inlines instead of macros where possible. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-04-10tcg: Introduce tcg_set_insn_start_paramRichard Henderson
The parameters for tcg_gen_insn_start are target_ulong, which may be split into two TCGArg parameters for storage in the opcode on 32-bit hosts. Fixes the ARM target and its direct use of tcg_set_insn_param, which would set the wrong argument in the 64-on-32 case. Cc: qemu-stable@nongnu.org Reported-by: alarson@ddci.com Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180410003558.2470-1-richard.henderson@linaro.org Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-08tcg: Add generic vector ops for multiplicationRichard Henderson
Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08tcg: Add generic vector ops for constant shiftsRichard Henderson
Opcodes are added for scalar and vector shifts, but considering the varied semantics of these do not expose them to the front ends. Do go ahead and provide them in case they are needed for backend expansion. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08tcg: Add generic vector expandersRichard Henderson
Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-08tcg: Add types and basic operations for host vectorsRichard Henderson
Nothing uses or enables them yet. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-12-29tcg: Allow 6 arguments to TCG helpersRichard Henderson
We already handle this in the backends, and the lifetime datum for the TCGOp is already large enough. Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-12-29tcg: Add tcg_signed_condRichard Henderson
Complimenting the existing tcg_unsigned_cond. Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-12-29tcg: Generalize TCGOp parametersRichard Henderson
We had two fields specific to INDEX_op_call. Rename these and add some macros so that the fields may be reused for other opcodes. Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-12-29tcg: Dynamically allocate TCGOpsRichard Henderson
With no fixed array allocation, we can't overflow a buffer. This will be important as optimizations related to host vectors may expand the number of ops used. Use QTAILQ to link the ops together. Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-12-29tcg: Remove TCGV_UNUSED* and TCGV_IS_UNUSED*Richard Henderson
These are now trivial sets and tests against NULL. Unwrap. Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24tcg: Initialize cpu_env genericallyRichard Henderson
This is identical for each target. So, move the initialization to common code. Move the variable itself out of tcg_ctx and name it cpu_env to minimize changes within targets. This also means we can remove tcg_global_reg_new_{ptr,i32,i64}, since there are no longer global-register temps created by targets. Reviewed-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24tcg: enable multiple TCG contexts in softmmuEmilio G. Cota
This enables parallel TCG code generation. However, we do not take advantage of it yet since tb_lock is still held during tb_gen_code. In user-mode we use a single TCG context; see the documentation added to tcg_region_init for the rationale. Note that targets do not need any conversion: targets initialize a TCGContext (e.g. defining TCG globals), and after this initialization has finished, the context is cloned by the vCPU threads, each of them keeping a separate copy. TCG threads claim one entry in tcg_ctxs[] by atomically increasing n_tcg_ctxs. Do not be too annoyed by the subsequent atomic_read's of that variable and tcg_ctxs; they are there just to play nice with analysis tools such as thread sanitizer. Note that we do not allocate an array of contexts (we allocate an array of pointers instead) because when tcg_context_init is called, we do not know yet how many contexts we'll use since the bool behind qemu_tcg_mttcg_enabled() isn't set yet. Previous patches folded some TCG globals into TCGContext. The non-const globals remaining are only set at init time, i.e. before the TCG threads are spawned. Here is a list of these set-at-init-time globals under tcg/: Only written by tcg_context_init: - indirect_reg_alloc_order - tcg_op_defs Only written by tcg_target_init (called from tcg_context_init): - tcg_target_available_regs - tcg_target_call_clobber_regs - arm: arm_arch, use_idiv_instructions - i386: have_cmov, have_bmi1, have_bmi2, have_lzcnt, have_movbe, have_popcnt - mips: use_movnz_instructions, use_mips32_instructions, use_mips32r2_instructions, got_sigill (tcg_target_detect_isa) - ppc: have_isa_2_06, have_isa_3_00, tb_ret_addr - s390: tb_ret_addr, s390_facilities - sparc: qemu_ld_trampoline, qemu_st_trampoline (build_trampolines), use_vis3_instructions Only written by tcg_prologue_init: - 'struct jit_code_entry one_entry' - aarch64: tb_ret_addr - arm: tb_ret_addr - i386: tb_ret_addr, guest_base_flags - ia64: tb_ret_addr - mips: tb_ret_addr, bswap32_addr, bswap32u_addr, bswap64_addr Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24tcg: introduce regions to split code_gen_bufferEmilio G. Cota
This is groundwork for supporting multiple TCG contexts. The naive solution here is to split code_gen_buffer statically among the TCG threads; this however results in poor utilization if translation needs are different across TCG threads. What we do here is to add an extra layer of indirection, assigning regions that act just like pages do in virtual memory allocation. (BTW if you are wondering about the chosen naming, I did not want to use blocks or pages because those are already heavily used in QEMU). We use a global lock to serialize allocations as well as statistics reporting (we now export the size of the used code_gen_buffer with tcg_code_size()). Note that for the allocator we could just use a counter and atomic_inc; however, that would complicate the gathering of tcg_code_size()-like stats. So given that the region operations are not a fast path, a lock seems the most reasonable choice. The effectiveness of this approach is clear after seeing some numbers. I used the bootup+shutdown of debian-arm with '-tb-size 80' as a benchmark. Note that I'm evaluating this after enabling per-thread TCG (which is done by a subsequent commit). * -smp 1, 1 region (entire buffer): qemu: flush code_size=83885014 nb_tbs=154739 avg_tb_size=357 qemu: flush code_size=83884902 nb_tbs=153136 avg_tb_size=363 qemu: flush code_size=83885014 nb_tbs=152777 avg_tb_size=364 qemu: flush code_size=83884950 nb_tbs=150057 avg_tb_size=373 qemu: flush code_size=83884998 nb_tbs=150234 avg_tb_size=373 qemu: flush code_size=83885014 nb_tbs=154009 avg_tb_size=360 qemu: flush code_size=83885014 nb_tbs=151007 avg_tb_size=370 qemu: flush code_size=83885014 nb_tbs=151816 avg_tb_size=367 That is, 8 flushes. * -smp 8, 32 regions (80/32 MB per region) [i.e. this patch]: qemu: flush code_size=76328008 nb_tbs=141040 avg_tb_size=356 qemu: flush code_size=75366534 nb_tbs=138000 avg_tb_size=361 qemu: flush code_size=76864546 nb_tbs=140653 avg_tb_size=361 qemu: flush code_size=76309084 nb_tbs=135945 avg_tb_size=375 qemu: flush code_size=74581856 nb_tbs=132909 avg_tb_size=375 qemu: flush code_size=73927256 nb_tbs=135616 avg_tb_size=360 qemu: flush code_size=78629426 nb_tbs=142896 avg_tb_size=365 qemu: flush code_size=76667052 nb_tbs=138508 avg_tb_size=368 Again, 8 flushes. Note how buffer utilization is not 100%, but it is close. Smaller region sizes would yield higher utilization, but we want region allocation to be rare (it acquires a lock), so we do not want to go too small. * -smp 8, static partitioning of 8 regions (10 MB per region): qemu: flush code_size=21936504 nb_tbs=40570 avg_tb_size=354 qemu: flush code_size=11472174 nb_tbs=20633 avg_tb_size=370 qemu: flush code_size=11603976 nb_tbs=21059 avg_tb_size=365 qemu: flush code_size=23254872 nb_tbs=41243 avg_tb_size=377 qemu: flush code_size=28289496 nb_tbs=52057 avg_tb_size=358 qemu: flush code_size=43605160 nb_tbs=78896 avg_tb_size=367 qemu: flush code_size=45166552 nb_tbs=82158 avg_tb_size=364 qemu: flush code_size=63289640 nb_tbs=116494 avg_tb_size=358 qemu: flush code_size=51389960 nb_tbs=93937 avg_tb_size=362 qemu: flush code_size=59665928 nb_tbs=107063 avg_tb_size=372 qemu: flush code_size=38380824 nb_tbs=68597 avg_tb_size=374 qemu: flush code_size=44884568 nb_tbs=79901 avg_tb_size=376 qemu: flush code_size=50782632 nb_tbs=90681 avg_tb_size=374 qemu: flush code_size=39848888 nb_tbs=71433 avg_tb_size=372 qemu: flush code_size=64708840 nb_tbs=119052 avg_tb_size=359 qemu: flush code_size=49830008 nb_tbs=90992 avg_tb_size=362 qemu: flush code_size=68372408 nb_tbs=123442 avg_tb_size=368 qemu: flush code_size=33555560 nb_tbs=59514 avg_tb_size=378 qemu: flush code_size=44748344 nb_tbs=80974 avg_tb_size=367 qemu: flush code_size=37104248 nb_tbs=67609 avg_tb_size=364 That is, 20 flushes. Note how a static partitioning approach uses the code buffer poorly, leading to many unnecessary flushes. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24tcg: distribute profiling counters across TCGContext'sEmilio G. Cota
This is groundwork for supporting multiple TCG contexts. To avoid scalability issues when profiling info is enabled, this patch makes the profiling info counters distributed via the following changes: 1) Consolidate profile info into its own struct, TCGProfile, which TCGContext also includes. Note that tcg_table_op_count is brought into TCGProfile after dropping the tcg_ prefix. 2) Iterate over the TCG contexts in the system to obtain the total counts. This change also requires updating the accessors to TCGProfile fields to use atomic_read/set whenever there may be conflicting accesses (as defined in C11) to them. Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24gen-icount: fold exitreq_label into TCGContextEmilio G. Cota
Groundwork for supporting multiple TCG contexts. Reviewed-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24tcg: define tcg_init_ctx and make tcg_ctx a pointerEmilio G. Cota
Groundwork for supporting multiple TCG contexts. The core of this patch is this change to tcg/tcg.h: > -extern TCGContext tcg_ctx; > +extern TCGContext tcg_init_ctx; > +extern TCGContext *tcg_ctx; Note that for now we set *tcg_ctx to whatever TCGContext is passed to tcg_context_init -- in this case &tcg_init_ctx. Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
generated by cgit v1.2.3 (git 2.26.2) at 2024-12-16 06:30:17 +0000