Re: [Qemu-devel] [PATCH v2] Do not use slow [*] expansion for GPIO creation

[Daniel P. Berrange]

On Fri, Jul 31, 2015 at 03:23:22PM +0300, Pavel Fedin wrote:
> Expansion of [*] suffix is very slow because index expansion is done using
> trial and error strategy, starting every time from zero and retrying with
> the next index until insertion succeeds. With large number of already added
> properties this process takes huge amount of time (O(n^2) complexity).
> 
> Some architectures (like ARM) use very large amount of IRQ pins in interrupt
> controller models. This flaw makes machine startup extremely slow
> (~20 seconds for ARM64 with 32 CPUs. This patch decreases this time down to
> ~10 seconds.
> 
> Also in qdev_init_gpio_out_named() memset() is now called only once for the
> whole array instead of per-cell cleaning
> 
> Signed-off-by: Pavel Fedin <address@hidden>
> ---
>  hw/core/qdev.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)

Reviewed-by: Daniel P. Berrange <address@hidden>


Regards,
Daniel
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