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  1. 16 6月, 2018 5 次提交
    • E
      tcg: track TBs with per-region BST's · be2cdc5e
      由 Emilio G. Cota 提交于 
      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: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: NEmilio G. Cota <cota@braap.org>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
      be2cdc5e
    • E
      qht: return existing entry when qht_insert fails · 32359d52
      由 Emilio G. Cota 提交于 
      The meaning of "existing" is now changed to "matches in hash and
ht->cmp result". This is saner than just checking the pointer value.
Suggested-by: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: NEmilio G. Cota <cota@braap.org>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
      32359d52
    • E
      qht: require a default comparison function · 61b8cef1
      由 Emilio G. Cota 提交于 
      qht_lookup now uses the default cmp function. qht_lookup_custom is defined
to retain the old behaviour, that is a cmp function is explicitly provided.

qht_insert will gain use of the default cmp in the next patch.

Note that we move qht_lookup_custom's @func to be the last argument,
which makes the new qht_lookup as simple as possible.
Instead of this (i.e. keeping @func 2nd):
0000000000010750 <qht_lookup>:
   10750:       89 d1                   mov    %edx,%ecx
   10752:       48 89 f2                mov    %rsi,%rdx
   10755:       48 8b 77 08             mov    0x8(%rdi),%rsi
   10759:       e9 22 ff ff ff          jmpq   10680 <qht_lookup_custom>
   1075e:       66 90                   xchg   %ax,%ax

We get:
0000000000010740 <qht_lookup>:
   10740:       48 8b 4f 08             mov    0x8(%rdi),%rcx
   10744:       e9 37 ff ff ff          jmpq   10680 <qht_lookup_custom>
   10749:       0f 1f 80 00 00 00 00    nopl   0x0(%rax)
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: NEmilio G. Cota <cota@braap.org>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
      61b8cef1
    • J
      tcg/i386: Use byte form of xgetbv instruction · 1019242a
      由 John Arbuckle 提交于 
      The assembler in most versions of Mac OS X is pretty old and does not
support the xgetbv instruction.  To go around this problem, the raw
encoding of the instruction is used instead.
Signed-off-by: NJohn Arbuckle <programmingkidx@gmail.com>
Message-Id: <20180604215102.11002-1-programmingkidx@gmail.com>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
      1019242a
    • P
      Merge remote-tracking branch... · 42747d6a
      由 Peter Maydell 提交于 
      Merge remote-tracking branch 'remotes/edgar/tags/edgar/xilinx-next-2018-06-15.for-upstream' into staging

xilinx-next-2018-06-15.for-upstream

# gpg: Signature made Fri 15 Jun 2018 15:32:47 BST
# gpg:                using RSA key 29C596780F6BCA83
# gpg: Good signature from "Edgar E. Iglesias (Xilinx key) <edgar.iglesias@xilinx.com>"
# gpg:                 aka "Edgar E. Iglesias <edgar.iglesias@gmail.com>"
# Primary key fingerprint: AC44 FEDC 14F7 F1EB EDBF  4151 29C5 9678 0F6B CA83

* remotes/edgar/tags/edgar/xilinx-next-2018-06-15.for-upstream:
  target-microblaze: Rework NOP/zero instruction handling
  target-microblaze: mmu: Correct masking of output addresses
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
      42747d6a
  3. 15 6月, 2018 35 次提交