Re: [PATCH 3/3] kernel-shark: Fix a bug in ksmodel_set_next_bin_edge()

[Slavomir Kaslev <kaslevs@vmware.com>]

On Thu, Feb 21, 2019 at 02:42:05PM +0200, Yordan Karadzhov wrote:
> The modification of the last bin of the model makes no sense (this is
> my mistake). The comment above the code that is doing this modification
> is partially correct, however it speaks about increasing the size of
> the last bin, while the code below the comment changes the lower edge
> of this bin. The actual increase of the size of the last bin is done in
> ksmodel_set_upper_edge() where the lower edge of the Upper Overflow bin
> gets shifted (max + 1). This effectively increases the size of the last bin.
> 
> Reported-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
> Fixes: f97e31f00 ("kernel-shark-qt: Introduce the visualization model ..")
> Signed-off-by: Yordan Karadzhov <ykaradzhov@vmware.com>
> ---
>  kernel-shark/src/libkshark-model.c | 9 ---------
>  1 file changed, 9 deletions(-)
> 
> diff --git a/kernel-shark/src/libkshark-model.c b/kernel-shark/src/libkshark-model.c
> index b6d3612..4bd1e2c 100644
> --- a/kernel-shark/src/libkshark-model.c
> +++ b/kernel-shark/src/libkshark-model.c
> @@ -266,15 +266,6 @@ static void ksmodel_set_next_bin_edge(struct kshark_trace_histo *histo,
>  	/* Calculate the beginning of the next bin. */
>  	time = histo->min + next_bin * histo->bin_size;
>  
> -	/*
> -	 * The timestamp of the very last entry of the dataset can be exactly
> -	 * equal to the value of the upper edge of the range. This is very
> -	 * likely to happen when we use ksmodel_set_in_range_bining(). In this
> -	 * case we have to increase the size of the very last bin in order to
> -	 * make sure that the last entry of the dataset will fall into it.
> -	 */
> -	if (next_bin == histo->n_bins - 1)
> -		++time;
>  	/*
>  	 * Find the index of the first entry inside
>  	 * the next bin (timestamp > time).
> -- 
> 2.17.1
> 

Patches 1, 2 and 3 look good to me.

Acked-by: Slavomir Kaslev <kaslevs@vmware.com>

Side note: ksmodel_shift_backward/ksmodel_shift_forward look pretty similar. Can
they be generalized to an either-directional ksmodel_shift taking the shift
parameter as signed? If ksmodel_shift_backward/ksmodel_shift_forward need to be
kept for backward compatibility, they can call ksmodel_shift (with a flipped
sign in the backward case).

Thank you,

-- Slavi