From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dibyendu Majumdar <mobile@majumdar.org.uk>
Subject: Re: Sparse 0.5.1 RC5 released.
Date: Sun, 13 Aug 2017 15:44:41 +0100
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To: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Christopher Li <sparse@chrisli.org>, Linux-Sparse <linux-sparse@vger.kernel.org>, Ramsay Jones <ramsay@ramsayjones.plus.com>, Lance Richardson <lrichard@redhat.com>, Michael Stefaniuc <mstefani@mykolab.com>

On 13 August 2017 at 15:18, Luc Van Oostenryck
<luc.vanoostenryck@gmail.com> wrote:
> On Sun, Aug 13, 2017 at 3:18 PM, Dibyendu Majumdar
> <mobile@majumdar.org.uk> wrote:
>
>>> Care to send your code, I can see where the problem could be?
>>
>> Yes apologies I should have mentioned the test case:
>>
>> https://github.com/dibyendumajumdar/dmr_c/blob/master/tests/lcc/cq.c
>
> No problem.
>
>> I am checking whether the slowdown is due to some other factor such as:
>
> I just gave a try and, I was a bit surprised as with the current master,
> here it takes me about 5s to get the output of test-linearize (which I find
> already a bit slow). It's far far from the time you have.
>
> OTOH with -rc4, it takes only 0.05s !
>
> The situation is really weird, it's an interaction between the patches:
> - remove single-store shortcut (first slowdown to 0.8s)
> - fix ptrlist corruption while killing unreachable BBs (second slowdown to 2.9s)
> - mark pseudo users as deleted instead of removing them (third slowdown to 5.5s)
>
> All three patches were expected to create *some* slowdown,
> the first one very obviously and much more than the others.
>
> It's interesting to note that without the 'remove single shortcut' patch, the
> two others ones don't seem to have a significative effect on the time.
>

Yes, reinstating the single store shortcut reduces time from 8.3 secs
to 0.16 seconds.

Regards
Dibyendu