Fix performance regression in qemu_get_ram_ptr
When the commit f471a17e9d869df3c6573f7ec02c4725676d6f3a converted the
ram_blocks structure to QLIST, it also removed the conditional check before
switching the current block at the beginning of the list.
In the common use case where ram_blocks has a few blocks with only one
frequently accessed (the main RAM), this has a performance impact as it
performs the useless list operations on each call (which are on a really
hot path).
On my machine emulation (ARM on amd64), this patch reduces the
percentage of CPU time spent in qemu_get_ram_ptr from 6.3% to 2.1% in the
profiling of a full boot.
Signed-off-by: Vincent Palatin <[email protected]>
Signed-off-by: Anthony Liguori <[email protected]>
1 file changed
