- 26 10月, 2017 22 次提交
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由 Eric Blake 提交于
In the continuing quest to make more things byte-based, change the internal iteration of img_compare(). We can finally drop the TODO assertions added earlier, now that the entire algorithm is byte-based and no longer has to shift from bytes to sectors. Most of the change is mechanical ('total_sectors' becomes 'total_size', 'sector_num' becomes 'offset', 'nb_sectors' becomes 'chunk', 'progress_base' goes from sectors to bytes); some of it is also a cleanup (sectors_to_bytes() is now unused, loss of variable 'count' added earlier in commit 51b0a488). Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
In the continuing quest to make more things byte-based, change the internal iteration of img_rebase(). We can finally drop the TODO assertion added earlier, now that the entire algorithm is byte-based and no longer has to shift from bytes to sectors. Most of the change is mechanical ('num_sectors' becomes 'size', 'sector' becomes 'offset', 'n' goes from sectors to bytes); some of it is also a cleanup (use of MIN() instead of open-coding, loss of variable 'count' added earlier in commit d6a644bb). Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
In the continuing quest to make more things byte-based, change compare_sectors(), renaming it to compare_buffers() in the process. Note that one caller (qemu-img compare) only cares about the first difference, while the other (qemu-img rebase) cares about how many consecutive sectors have the same equal/different status; however, this patch does not bother to micro-optimize the compare case to avoid the comparisons of sectors beyond the first mismatch. Both callers are always passing valid buffers in, so the initial check for buffer size can be turned into an assertion. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
Continue on the quest to make more things byte-based instead of sector-based. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
If a read error is encountered during 'qemu-img compare', we were printing the "Error while reading offset ..." message twice; this was because our helper function was awkward, printing output on some but not all paths. Fix it to consistently report errors on all paths, so that the callers do not risk a redundant message, and update the testsuite for the improved output. Further simplify the code by hoisting the conversion from an error message to an exit code into the helper function, rather than repeating that logic at all callers (yes, the helper function is now less generic, but it's a net win in lines of code). Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
During 'qemu-img compare', when we are checking that an allocated portion of one file is all zeros, we don't need to waste time computing how many additional sectors after the first non-zero byte are also non-zero. Create a new helper find_nonzero() to do the check for a first non-zero sector, and rebase check_empty_sectors() to use it. The new interface intentionally uses bytes in its interface, even though it still crawls the buffer a sector at a time; it is robust to a partial sector at the end of the buffer. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
Compare the following images with all-zero contents: $ truncate --size 1M A $ qemu-img create -f qcow2 -o preallocation=off B 1G $ qemu-img create -f qcow2 -o preallocation=metadata C 1G On my machine, the difference is noticeable for pre-patch speeds, with more than an order of magnitude in difference caused by the choice of preallocation in the qcow2 file: $ time ./qemu-img compare -f raw -F qcow2 A B Warning: Image size mismatch! Images are identical. real 0m0.014s user 0m0.007s sys 0m0.007s $ time ./qemu-img compare -f raw -F qcow2 A C Warning: Image size mismatch! Images are identical. real 0m0.341s user 0m0.144s sys 0m0.188s Why? Because bdrv_is_allocated() returns false for image B but true for image C, throwing away the fact that both images know via lseek(SEEK_HOLE) that the entire image still reads as zero. From there, qemu-img ends up calling bdrv_pread() for every byte of the tail, instead of quickly looking for the next allocation. The solution: use block_status instead of is_allocated, giving: $ time ./qemu-img compare -f raw -F qcow2 A C Warning: Image size mismatch! Images are identical. real 0m0.014s user 0m0.011s sys 0m0.003s which is on par with the speeds for no pre-allocation. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Reviewed-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
As long as we are querying the status for a chunk smaller than the known image size, we are guaranteed that a successful return will have set pnum to a non-zero size (pnum is zero only for queries beyond the end of the file). Use that to slightly simplify the calculation of the current chunk size being compared. Likewise, we don't have to shrink the amount of data operated on until we know we have to read the file, and therefore have to fit in the bounds of our buffer. Also, note that 'total_sectors_over' is equivalent to 'progress_base'. With these changes in place, sectors_to_process() is now dead code, and can be removed. Signed-off-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
We are gradually moving away from sector-based interfaces, towards byte-based. In the common case, allocation is unlikely to ever use values that are not naturally sector-aligned, but it is possible that byte-based values will let us be more precise about allocation at the end of an unaligned file that can do byte-based access. Changing the name of the function from bdrv_get_block_status_above() to bdrv_block_status_above() ensures that the compiler enforces that all callers are updated. Likewise, since it a byte interface allows an offset mapping that might not be sector aligned, split the mapping out of the return value and into a pass-by-reference parameter. For now, the io.c layer still assert()s that all uses are sector-aligned, but that can be relaxed when a later patch implements byte-based block status in the drivers. For the most part this patch is just the addition of scaling at the callers followed by inverse scaling at bdrv_block_status(), plus updates for the new split return interface. But some code, particularly bdrv_block_status(), gets a lot simpler because it no longer has to mess with sectors. Likewise, mirror code no longer computes s->granularity >> BDRV_SECTOR_BITS, and can therefore drop an assertion about alignment because the loop no longer depends on alignment (never mind that we don't really have a driver that reports sub-sector alignments, so it's not really possible to test the effect of sub-sector mirroring). Fix a neighboring assertion to use is_power_of_2 while there. For ease of review, bdrv_get_block_status() was tackled separately. Signed-off-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
We are gradually converting to byte-based interfaces, as they are easier to reason about than sector-based. Convert another internal type (no semantic change), and rename it to match the corresponding public function rename. Signed-off-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
We are gradually converting to byte-based interfaces, as they are easier to reason about than sector-based. Convert another internal function (no semantic change). Signed-off-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
We are gradually converting to byte-based interfaces, as they are easier to reason about than sector-based. Convert another internal type (no semantic change), and rename it to match the corresponding public function rename. Signed-off-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
We are gradually converting to byte-based interfaces, as they are easier to reason about than sector-based. Convert another internal function (no semantic change); and as with its public counterpart, rename to bdrv_co_block_status() and split the offset return, to make the compiler enforce that we catch all uses. For now, we assert that callers and the return value still use aligned data, but ultimately, this will be the function where we hand off to a byte-based driver callback, and will eventually need to add logic to ensure we round calls according to the driver's request_alignment then touch up the result handed back to the caller, to start permitting a caller to pass unaligned offsets. Note that we are now prepared to accepts 'bytes' larger than INT_MAX; this is okay as long as we clamp things internally before violating any 32-bit limits, and makes no difference to how a client will use the information (clients looping over the entire file must already be prepared for consecutive calls to return the same status, as drivers are already free to return shorter-than-maximal status due to any other convenient split points, such as when the L2 table crosses cluster boundaries in qcow2). Signed-off-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
We are gradually moving away from sector-based interfaces, towards byte-based. In the common case, allocation is unlikely to ever use values that are not naturally sector-aligned, but it is possible that byte-based values will let us be more precise about allocation at the end of an unaligned file that can do byte-based access. Changing the name of the function from bdrv_get_block_status() to bdrv_block_status() ensures that the compiler enforces that all callers are updated. For now, the io.c layer still assert()s that all callers are sector-aligned, but that can be relaxed when a later patch implements byte-based block status in the drivers. There was an inherent limitation in returning the offset via the return value: we only have room for BDRV_BLOCK_OFFSET_MASK bits, which means an offset can only be mapped for sector-aligned queries (or, if we declare that non-aligned input is at the same relative position modulo 512 of the answer), so the new interface also changes things to return the offset via output through a parameter by reference rather than mashed into the return value. We'll have some glue code that munges between the two styles until we finish converting all uses. For the most part this patch is just the addition of scaling at the callers followed by inverse scaling at bdrv_block_status(), coupled with the tweak in calling convention. But some code, particularly bdrv_is_allocated(), gets a lot simpler because it no longer has to mess with sectors. For ease of review, bdrv_get_block_status_above() will be tackled separately. Signed-off-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
We are gradually converting to byte-based interfaces, as they are easier to reason about than sector-based. Continue by converting an internal function (no semantic change), and simplifying its caller accordingly. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
We are gradually converting to byte-based interfaces, as they are easier to reason about than sector-based. Change the internal loop iteration of zeroing a device to track by bytes instead of sectors (although we are still guaranteed that we iterate by steps that are sector-aligned). Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
We are gradually converting to byte-based interfaces, as they are easier to reason about than sector-based. Convert another internal function (no semantic change), and rename it to is_zero() in the process. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
In the process of converting sector-based interfaces to bytes, I'm finding it easier to represent a byte count as a 64-bit integer at the block layer (even if we are internally capped by SIZE_MAX or even INT_MAX for individual transactions, it's still nicer to not have to worry about truncation/overflow issues on as many variables). Update the signature of bdrv_round_to_clusters() to uniformly use int64_t, matching the signature already chosen for bdrv_is_allocated and the fact that off_t is also a signed type, then adjust clients according to the required fallout (even where the result could now exceed 32 bits, no client is directly assigning the result into a 32-bit value without breaking things into a loop first). Signed-off-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
Not all callers care about which BDS owns the mapping for a given range of the file, or where the zeroes lie within that mapping. In particular, bdrv_is_allocated() cares more about finding the largest run of allocated data from the guest perspective, whether or not that data is consecutive from the host perspective, and whether or not the data reads as zero. Therefore, doing subsequent refinements such as checking how much of the format-layer allocation also satisfies BDRV_BLOCK_ZERO at the protocol layer is wasted work - in the best case, it just costs extra CPU cycles during a single bdrv_is_allocated(), but in the worst case, it results in a smaller *pnum, and forces callers to iterate through more status probes when visiting the entire file for even more extra CPU cycles. This patch only optimizes the block layer (no behavior change when want_zero is true, but skip unnecessary effort when it is false). Then when subsequent patches tweak the driver callback to be byte-based, we can also pass this hint through to the driver. Tweak BdrvCoGetBlockStatusData to declare arguments in parameter order, rather than mixing things up (minimizing padding is not necessary here). Signed-off-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
Not all callers care about which BDS owns the mapping for a given range of the file. This patch merely simplifies the callers by consolidating the logic in the common call point, while guaranteeing a non-NULL file to all the driver callbacks, for no semantic change. The only caller that does not care about pnum is bdrv_is_allocated, as invoked by vvfat; we can likewise add assertions that the rest of the stack does not have to worry about a NULL pnum. Furthermore, this will also set the stage for a future cleanup: when a caller does not care about which BDS owns an offset, it would be nice to allow the driver to optimize things to not have to return BDRV_BLOCK_OFFSET_VALID in the first place. In the case of fragmented allocation (for example, it's fairly easy to create a qcow2 image where consecutive guest addresses are not at consecutive host addresses), the current contract requires bdrv_get_block_status() to clamp *pnum to the limit where host addresses are no longer consecutive, but allowing a NULL file means that *pnum could be set to the full length of known-allocated data. Signed-off-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Kevin Wolf 提交于
This changes test case 191 to include a backing image that has backing_fmt set in the image file, but is referenced by node name in the qemu command line. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NEric Blake <eblake@redhat.com>
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由 Peter Krempa 提交于
When referring to a backing file of an image via node name bdrv_open_backing_file would add the 'driver' option to the option list filling it with the backing format driver. This breaks construction of the backing chain via -blockdev, as bdrv_open_inherit reports an error if both 'reference' and 'options' are provided. $ qemu-img create -f raw /tmp/backing.raw 64M $ qemu-img create -f qcow2 -F raw -b /tmp/backing.raw /tmp/test.qcow2 $ qemu-system-x86_64 \ -blockdev driver=file,filename=/tmp/backing.raw,node-name=backing \ -blockdev driver=qcow2,file.driver=file,file.filename=/tmp/test.qcow2,node-name=root,backing=backing qemu-system-x86_64: -blockdev driver=qcow2,file.driver=file,file.filename=/tmp/test.qcow2,node-name=root,backing=backing: Could not open backing file: Cannot reference an existing block device with additional options or a new filename Signed-off-by: NPeter Krempa <pkrempa@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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- 25 10月, 2017 18 次提交
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由 Peter Maydell 提交于
TCG patch queue # gpg: Signature made Wed 25 Oct 2017 10:30:18 BST # gpg: using RSA key 0x64DF38E8AF7E215F # gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" # Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A 05C0 64DF 38E8 AF7E 215F * remotes/rth/tags/pull-tcg-20171025: (51 commits) translate-all: exit from tb_phys_invalidate if qht_remove fails tcg: Initialize cpu_env generically tcg: enable multiple TCG contexts in softmmu tcg: introduce regions to split code_gen_buffer translate-all: use qemu_protect_rwx/none helpers osdep: introduce qemu_mprotect_rwx/none tcg: allocate optimizer temps with tcg_malloc tcg: distribute profiling counters across TCGContext's tcg: introduce **tcg_ctxs to keep track of all TCGContext's gen-icount: fold exitreq_label into TCGContext tcg: define tcg_init_ctx and make tcg_ctx a pointer tcg: take tb_ctx out of TCGContext translate-all: report correct avg host TB size exec-all: rename tb_free to tb_remove translate-all: use a binary search tree to track TBs in TBContext tcg: Remove CF_IGNORE_ICOUNT tcg: Add CF_LAST_IO + CF_USE_ICOUNT to CF_HASH_MASK cpu-exec: lookup/generate TB outside exclusive region during step_atomic tcg: check CF_PARALLEL instead of parallel_cpus target/sparc: check CF_PARALLEL instead of parallel_cpus ... Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
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由 Peter Maydell 提交于
migration/next for 20171023 # gpg: Signature made Mon 23 Oct 2017 17:05:14 BST # gpg: using RSA key 0xF487EF185872D723 # gpg: Good signature from "Juan Quintela <quintela@redhat.com>" # gpg: aka "Juan Quintela <quintela@trasno.org>" # Primary key fingerprint: 1899 FF8E DEBF 58CC EE03 4B82 F487 EF18 5872 D723 * remotes/juanquintela/tags/migration/20171023: (21 commits) migration: Improve migration thread error handling qapi: Fix grammar in x-multifd-page-count descriptions migration: add bitmap for received page migration: introduce qemu_ufd_copy_ioctl helper migration: postcopy_place_page factoring out migration: new ram_init_bitmaps() migration: clean up xbzrle cache init/destroy migration: provide ram_state_cleanup migration: provide ram_state_init() migration: pause-before-switchover for postcopy migration: allow cancel to unpause migrate: HMP migate_continue migration: migrate-continue migration: Wait for semaphore before completing migration migration: Add 'pre-switchover' and 'device' statuses migration: Add 'pause-before-switchover' capability migration: Make cache_init() take an error parameter migration: Move xbzrle cache resize error handling to xbzrle_cache_resize migration: Make cache size elements use the right types migratiom: Remove max_item_age parameter ... Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
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由 Emilio G. Cota 提交于
Two or more threads might race while invalidating the same TB. We currently do not check for this at all despite taking tb_lock, which means we would wrongly invalidate the same TB more than once. This bug has actually been hit by users: I recently saw a report on IRC, although I have yet to see the corresponding test case. Fix this by using qht_remove as the synchronization point; if it fails, that means the TB has already been invalidated, and therefore there is nothing left to do in tb_phys_invalidate. Note that this solution works now that we still have tb_lock, and will continue working once we remove tb_lock. Reviewed-by: NRichard Henderson <richard.henderson@linaro.org> Signed-off-by: NEmilio G. Cota <cota@braap.org> Message-Id: <1508445114-4717-1-git-send-email-cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Richard Henderson 提交于
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: NEmilio G. Cota <cota@braap.org> Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
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: NRichard Henderson <rth@twiddle.net> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
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: NRichard Henderson <richard.henderson@linaro.org> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
The helpers require the address and size to be page-aligned, so do that before calling them. Reviewed-by: NRichard Henderson <rth@twiddle.net> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
Reviewed-by: NRichard Henderson <rth@twiddle.net> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
Groundwork for supporting multiple TCG contexts. While at it, also allocate temps_used directly as a bitmap of the required size, instead of using a bitmap of TCG_MAX_TEMPS via TCGTempSet. Performance-wise we lose about 1.12% in a translation-heavy workload such as booting+shutting down debian-arm: Performance counter stats for 'taskset -c 0 arm-softmmu/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=die-on-boot.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): exec time (s) Relative slowdown wrt original (%) --------------------------------------------------------------- original 20.213321616 0. tcg_malloc 20.441130078 1.1270214 TCGContext 20.477846517 1.3086662 g_malloc 20.780527895 2.8061013 The other two alternatives shown in the table are: - TCGContext: embed temps[TCG_MAX_TEMPS] and TCGTempSet used_temps in TCGContext. This is simple enough but it isn't faster than using tcg_malloc; moreover, it wastes memory. - g_malloc: allocate/deallocate both temps and used_temps every time tcg_optimize is executed. Suggested-by: NRichard Henderson <rth@twiddle.net> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
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: NRichard Henderson <rth@twiddle.net> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
Groundwork for supporting multiple TCG contexts. Note that having n_tcg_ctxs is unnecessary. However, it is convenient to have it, since it will simplify iterating over the array: we'll have just a for loop instead of having to iterate over a NULL-terminated array (which would require n+1 elems) or having to check with ifdef's for usermode/softmmu. Reviewed-by: NRichard Henderson <rth@twiddle.net> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
Groundwork for supporting multiple TCG contexts. Reviewed-by: NRichard Henderson <rth@twiddle.net> 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>
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由 Emilio G. Cota 提交于
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: NRichard Henderson <rth@twiddle.net> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
Groundwork for supporting multiple TCG contexts. Reviewed-by: NRichard Henderson <rth@twiddle.net> 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>
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由 Emilio G. Cota 提交于
Since commit 6e3b2bfd ("tcg: allocate TB structs before the corresponding translated code") we are not fully utilizing code_gen_buffer for translated code, and therefore are incorrectly reporting the amount of translated code as well as the average host TB size. Address this by: - Making the conscious choice of misreporting the total translated code; doing otherwise would mislead users into thinking "-tb-size" is not honoured. - Expanding tb_tree_stats to accurately count the bytes of translated code on the host, and using this for reporting the average tb host size, as well as the expansion ratio. In the future we might want to consider reporting the accurate numbers for the total translated code, together with a "bookkeeping/overhead" field to account for the TB structs. Reviewed-by: NRichard Henderson <rth@twiddle.net> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
We don't really free anything in this function anymore; we just remove the TB from the binary search tree. Suggested-by: NAlex Bennée <alex.bennee@linaro.org> Reviewed-by: NRichard Henderson <rth@twiddle.net> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Emilio G. Cota 提交于
This is a prerequisite for supporting multiple TCG contexts, since we will have threads generating code in separate regions of code_gen_buffer. For this we need a new field (.size) in struct tb_tc to keep track of the size of the translated code. This field uses a size_t to avoid adding a hole to the struct, although really an unsigned int would have been enough. The comparison function we use is optimized for the common case: insertions. Profiling shows that upon booting debian-arm, 98% of comparisons are between existing tb's (i.e. a->size and b->size are both !0), which happens during insertions (and removals, but those are rare). The remaining cases are lookups. From reading the glib sources we see that the first key is always the lookup key. However, the code does not assume this to always be the case because this behaviour is not guaranteed in the glib docs. However, we embed this knowledge in the code as a branch hint for the compiler. Note that tb_free does not free space in the code_gen_buffer anymore, since we cannot easily know whether the tb is the last one inserted in code_gen_buffer. The next patch in this series renames tb_free to tb_remove to reflect this. Performance-wise, lookups in tb_find_pc are the same as before: O(log n). However, insertions are O(log n) instead of O(1), which results in a small slowdown when booting debian-arm: Performance counter stats for 'build/arm-softmmu/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=img/arm/jessie-arm32.qcow2,id=myblock,index=0,if=none \ -device virtio-blk-device,drive=myblock \ -kernel img/arm/aarch32-current-linux-kernel-only.img \ -append console=ttyAMA0 root=/dev/vda1 \ -name arm,debug-threads=on -smp 1' (10 runs): - Before: 8048.598422 task-clock (msec) # 0.931 CPUs utilized ( +- 0.28% ) 16,974 context-switches # 0.002 M/sec ( +- 0.12% ) 0 cpu-migrations # 0.000 K/sec 10,125 page-faults # 0.001 M/sec ( +- 1.23% ) 35,144,901,879 cycles # 4.367 GHz ( +- 0.14% ) <not supported> stalled-cycles-frontend <not supported> stalled-cycles-backend 65,758,252,643 instructions # 1.87 insns per cycle ( +- 0.33% ) 10,871,298,668 branches # 1350.707 M/sec ( +- 0.41% ) 192,322,212 branch-misses # 1.77% of all branches ( +- 0.32% ) 8.640869419 seconds time elapsed ( +- 0.57% ) - After: 8146.242027 task-clock (msec) # 0.923 CPUs utilized ( +- 1.23% ) 17,016 context-switches # 0.002 M/sec ( +- 0.40% ) 0 cpu-migrations # 0.000 K/sec 18,769 page-faults # 0.002 M/sec ( +- 0.45% ) 35,660,956,120 cycles # 4.378 GHz ( +- 1.22% ) <not supported> stalled-cycles-frontend <not supported> stalled-cycles-backend 65,095,366,607 instructions # 1.83 insns per cycle ( +- 1.73% ) 10,803,480,261 branches # 1326.192 M/sec ( +- 1.95% ) 195,601,289 branch-misses # 1.81% of all branches ( +- 0.39% ) 8.828660235 seconds time elapsed ( +- 0.38% ) Reviewed-by: NRichard Henderson <rth@twiddle.net> Signed-off-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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由 Richard Henderson 提交于
Now that we have curr_cflags, we can include CF_USE_ICOUNT early and then remove it as necessary. Reviewed-by: NEmilio G. Cota <cota@braap.org> Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
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