Commit Graph

9 Commits

Author SHA1 Message Date
Alex Bennée
bf253ac606 accel/tcg: drop the use of CF_HASH_MASK and rename params
We don't really deal in cf_mask most of the time. The one time it's
relevant is when we want to remove an invalidated TB from the QHT
lookup. Everywhere else we should be looking up things without
CF_INVALID set.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210224165811.11567-4-alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-03-06 11:52:06 -08:00
Alex Bennée
c0ae396a81 accel/tcg: move CF_CLUSTER calculation to curr_cflags
There is nothing special about this compile flag that doesn't mean we
can't just compute it with curr_cflags() which we should be using when
building a new set.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210224165811.11567-3-alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-03-06 11:50:50 -08:00
Alex Bennée
6f04cb1c8f accel/tcg: rename tb_lookup__cpu_state and hoist state extraction
Having a function return either and valid TB and some system state
seems excessive. It will make the subsequent re-factoring easier if we
lookup the current state where we are.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210224165811.11567-2-alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-03-06 11:50:43 -08:00
Stefan Hajnoczi
d73415a315 qemu/atomic.h: rename atomic_ to qatomic_
clang's C11 atomic_fetch_*() functions only take a C11 atomic type
pointer argument. QEMU uses direct types (int, etc) and this causes a
compiler error when a QEMU code calls these functions in a source file
that also included <stdatomic.h> via a system header file:

  $ CC=clang CXX=clang++ ./configure ... && make
  ../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)

Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
searched GitHub for existing "qatomic_" users but there seem to be none.

This patch was generated using:

  $ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
    sort -u >/tmp/changed_identifiers
  $ for identifier in $(</tmp/changed_identifiers); do
        sed -i "s%\<$identifier\>%q$identifier%g" \
            $(git grep -I -l "\<$identifier\>")
    done

I manually fixed line-wrap issues and misaligned rST tables.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200923105646.47864-1-stefanha@redhat.com>
2020-09-23 16:07:44 +01:00
Peter Maydell
9fd9b7de61 accel/tcg: Consider cluster index in tb_lookup__cpu_state()
In commit f7b78602fd we added the CPU cluster number to the
cflags field of the TB hash; this included adding it to the value
kept in tb->cflags, since we pass that field directly into the hash
calculation in some places. Unfortunately we forgot to check whether
other parts of the code were doing comparisons against tb->cflags
that would need to be updated.

It turns out that there is exactly one such place: the
tb_lookup__cpu_state() function checks whether the TB it has
found in the tb_jmp_cache has a tb->cflags matching the cf_mask
that is passed in. The tb->cflags has the cluster_index in it
but the cf_mask does not.

Hoist the "add cluster index to the cf_mask" code up from
tb_htable_lookup() to tb_lookup__cpu_state() so it can be considered
in the "did this TB match in the jmp cache" condition, as well as
when we do the full hash lookup by physical PC, flags, etc.
(tb_htable_lookup() is only called from tb_lookup__cpu_state(),
so this change doesn't require any further knock-on changes.)

Fixes: f7b78602fd ("accel/tcg: Add cluster number to TCG TB hash")
Tested-by: Cleber Rosa <crosa@redhat.com>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reported-by: Howard Spoelstra <hsp.cat7@gmail.com>
Reported-by: Cleber Rosa <crosa@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20190205151810.571-1-peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-02-06 03:39:24 +00:00
Markus Armbruster
8f0a3716e4 Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes, with the change
to target/s390x/gen-features.c manually reverted, and blank lines
around deletions collapsed.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-3-armbru@redhat.com>
2018-02-09 05:05:11 +01:00
Emilio G. Cota
4e2ca83e71 tcg: define CF_PARALLEL and use it for TB hashing along with CF_COUNT_MASK
This will enable us to decouple code translation from the value
of parallel_cpus at any given time. It will also help us minimize
TB flushes when generating code via EXCP_ATOMIC.

Note that the declaration of parallel_cpus is brought to exec-all.h
to be able to define there the "curr_cflags" inline.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:41 -07:00
Emilio G. Cota
84f1c148da exec-all: bring tb->invalid into tb->cflags
This gets rid of a hole in struct TranslationBlock.

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>
2017-10-10 07:37:10 -07:00
Emilio G. Cota
f6bb84d531 tcg: consolidate TB lookups in tb_lookup__cpu_state
This avoids duplicating code. cpu_exec_step will also use the
new common function once we integrate parallel_cpus into tb->cflags.

Note that in this commit we also fix a race, described by Richard Henderson
during review. Think of this scenario with threads A and B:

   (A) Lookup succeeds for TB in hash without tb_lock
        (B) Sets the TB's tb->invalid flag
        (B) Removes the TB from tb_htable
        (B) Clears all CPU's tb_jmp_cache
   (A) Store TB into local tb_jmp_cache

Given that order of events, (A) will keep executing that invalid TB until
another flush of its tb_jmp_cache happens, which in theory might never happen.
We can fix this by checking the tb->invalid flag every time we look up a TB
from tb_jmp_cache, so that in the above scenario, next time we try to find
that TB in tb_jmp_cache, we won't, and will therefore be forced to look it
up in tb_htable.

Performance-wise, I measured a small improvement when booting debian-arm.
Note that inlining pays off:

 Performance counter stats for 'taskset -c 0 qemu-system-arm \
	-machine type=virt -nographic -smp 1 -m 4096 \
	-netdev user,id=unet,hostfwd=tcp::2222-:22 \
	-device virtio-net-device,netdev=unet \
	-drive file=jessie.qcow2,id=myblock,index=0,if=none \
	-device virtio-blk-device,drive=myblock \
	-kernel kernel.img -append console=ttyAMA0 root=/dev/vda1 \
	-name arm,debug-threads=on -smp 1' (10 runs):

Before:
      18714.917392 task-clock                #    0.952 CPUs utilized            ( +-  0.95% )
            23,142 context-switches          #    0.001 M/sec                    ( +-  0.50% )
                 1 CPU-migrations            #    0.000 M/sec
            10,558 page-faults               #    0.001 M/sec                    ( +-  0.95% )
    53,957,727,252 cycles                    #    2.883 GHz                      ( +-  0.91% ) [83.33%]
    24,440,599,852 stalled-cycles-frontend   #   45.30% frontend cycles idle     ( +-  1.20% ) [83.33%]
    16,495,714,424 stalled-cycles-backend    #   30.57% backend  cycles idle     ( +-  0.95% ) [66.66%]
    76,267,572,582 instructions              #    1.41  insns per cycle
                                             #    0.32  stalled cycles per insn  ( +-  0.87% ) [83.34%]
    12,692,186,323 branches                  #  678.186 M/sec                    ( +-  0.92% ) [83.35%]
       263,486,879 branch-misses             #    2.08% of all branches          ( +-  0.73% ) [83.34%]

      19.648474449 seconds time elapsed                                          ( +-  0.82% )

After, w/ inline (this patch):
      18471.376627 task-clock                #    0.955 CPUs utilized            ( +-  0.96% )
            23,048 context-switches          #    0.001 M/sec                    ( +-  0.48% )
                 1 CPU-migrations            #    0.000 M/sec
            10,708 page-faults               #    0.001 M/sec                    ( +-  0.81% )
    53,208,990,796 cycles                    #    2.881 GHz                      ( +-  0.98% ) [83.34%]
    23,941,071,673 stalled-cycles-frontend   #   44.99% frontend cycles idle     ( +-  0.95% ) [83.34%]
    16,161,773,848 stalled-cycles-backend    #   30.37% backend  cycles idle     ( +-  0.76% ) [66.67%]
    75,786,269,766 instructions              #    1.42  insns per cycle
                                             #    0.32  stalled cycles per insn  ( +-  1.24% ) [83.34%]
    12,573,617,143 branches                  #  680.708 M/sec                    ( +-  1.34% ) [83.33%]
       260,235,550 branch-misses             #    2.07% of all branches          ( +-  0.66% ) [83.33%]

      19.340502161 seconds time elapsed                                          ( +-  0.56% )

After, w/o inline:
      18791.253967 task-clock                #    0.954 CPUs utilized            ( +-  0.78% )
            23,230 context-switches          #    0.001 M/sec                    ( +-  0.42% )
                 1 CPU-migrations            #    0.000 M/sec
            10,563 page-faults               #    0.001 M/sec                    ( +-  1.27% )
    54,168,674,622 cycles                    #    2.883 GHz                      ( +-  0.80% ) [83.34%]
    24,244,712,629 stalled-cycles-frontend   #   44.76% frontend cycles idle     ( +-  1.37% ) [83.33%]
    16,288,648,572 stalled-cycles-backend    #   30.07% backend  cycles idle     ( +-  0.95% ) [66.66%]
    77,659,755,503 instructions              #    1.43  insns per cycle
                                             #    0.31  stalled cycles per insn  ( +-  0.97% ) [83.34%]
    12,922,780,045 branches                  #  687.702 M/sec                    ( +-  1.06% ) [83.34%]
       261,962,386 branch-misses             #    2.03% of all branches          ( +-  0.71% ) [83.35%]

      19.700174670 seconds time elapsed                                          ( +-  0.56% )

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>
2017-10-10 07:37:10 -07:00