Re: [PATCH 02/19] perf, sort: Add physid sorting based on mmap2 data

[Don Zickus <dzickus@redhat.com>]

On Wed, Mar 19, 2014 at 11:45:15AM +0100, Jiri Olsa wrote:
> > +static int64_t
> > +sort__physid_cmp(struct hist_entry *left, struct hist_entry *right)
> > +{
> > +        u64 l, r;
> > +        struct map *l_map = left->mem_info->daddr.map;
> > +        struct map *r_map = right->mem_info->daddr.map;
> > +
> > +	/* store all NULL mem maps at the bottom */
> > +	/* shouldn't even need this check, should have stubs */
> > +	if (!left->mem_info->daddr.map || !right->mem_info->daddr.map)
> > +		return 1;
> > +
> > +        /* group event types together */
> > +        if (left->cpumode > right->cpumode) return -1;
> > +        if (left->cpumode < right->cpumode) return 1;
> > +
> > +        if (l_map->maj > r_map->maj) return -1;
> > +        if (l_map->maj < r_map->maj) return 1;
> > +
> > +        if (l_map->min > r_map->min) return -1;
> > +        if (l_map->min < r_map->min) return 1;
> > +
> > +        if (l_map->ino > r_map->ino) return -1;
> > +        if (l_map->ino < r_map->ino) return 1;
> > +
> > +        if (l_map->ino_generation > r_map->ino_generation) return -1;
> > +        if (l_map->ino_generation < r_map->ino_generation) return 1;
> > +
> > +        /*
> > +         * Addresses with no major/minor numbers are assumed to be
> > +         * anonymous in userspace.  Sort those on pid then address.
> > +         *
> > +         * The kernel and non-zero major/minor mapped areas are
> > +         * assumed to be unity mapped.  Sort those on address then pid.
> > +         */
> > +
> > +        /* al_addr does all the right addr - start + offset calculations */
> > +        l = left->mem_info->daddr.al_addr;
> > +        r = right->mem_info->daddr.al_addr;
> > +
> > +        if (l_map->maj || l_map->min || l_map->ino || l_map-> ino_generation) {
> > +                /* mmapped areas */
> > +
> > +                /* hack to mark similar regions, 'right' is new entry */
> > +                /* entries with same maj/min/ino/inogen are in same address space */
> > +                right->color = TRUE;
> > +
> > +                if (l > r) return -1;
> > +                if (l < r) return 1;
> > +
> > +                /* sorting by iaddr makes calculations easier later */
> > +                if (left->mem_info->iaddr.al_addr > right->mem_info->iaddr.al_addr) return -1;
> > +                if (left->mem_info->iaddr.al_addr < right->mem_info->iaddr.al_addr) return 1;
> > +
> > +                if (left->thread->pid_ > right->thread->pid_) return -1;
> > +                if (left->thread->pid_ < right->thread->pid_) return 1;
> > +
> > +                if (left->thread->tid > right->thread->tid) return -1;
> > +                if (left->thread->tid < right->thread->tid) return 1;
> > +        } else if (left->cpumode == PERF_RECORD_MISC_KERNEL) {
> > +                /* kernel mapped areas where 'start' doesn't matter */
> > +
> > +                /* hack to mark similar regions, 'right' is new entry */
> > +                /* whole kernel region is in the same address space */
> > +                right->color = TRUE;
> > +
> > +                if (l > r) return -1;
> > +                if (l < r) return 1;
> > +
> > +                /* sorting by iaddr makes calculations easier later */
> > +                if (left->mem_info->iaddr.al_addr > right->mem_info->iaddr.al_addr) return -1;
> > +                if (left->mem_info->iaddr.al_addr < right->mem_info->iaddr.al_addr) return 1;
> > +
> > +                if (left->thread->pid_ > right->thread->pid_) return -1;
> > +                if (left->thread->pid_ < right->thread->pid_) return 1;
> > +
> > +                if (left->thread->tid > right->thread->tid) return -1;
> > +                if (left->thread->tid < right->thread->tid) return 1;
> > +        } else {
> > +                /* userspace anonymous */
> > +                if (left->thread->pid_ > right->thread->pid_) return -1;
> > +                if (left->thread->pid_ < right->thread->pid_) return 1;
> > +
> > +                if (left->thread->tid > right->thread->tid) return -1;
> > +                if (left->thread->tid < right->thread->tid) return 1;
> > +
> > +	         /* hack to mark similar regions, 'right' is new entry */
> > +                /* userspace anonymous address space is contained within pid */
> > +                right->color = TRUE;
> > +
> > +                if (l > r) return -1;
> > +                if (l < r) return 1;
> > +
> > +                /* sorting by iaddr makes calculations easier later */
> > +                if (left->mem_info->iaddr.al_addr > right->mem_info->iaddr.al_addr) return -1;
> > +                if (left->mem_info->iaddr.al_addr < right->mem_info->iaddr.al_addr) return 1;
> > +        }
> 
> do you need single column for 'physid' ?
> 
> my first idea was to have separate sort entries for all checked entries:
> (same way like for memory memory_sort_dimensions)
> 
>   - mem_info->daddr.al_addr (we already have 'addr' check)
>   - mem_info->iaddr.al_addr
>   - thread->pid_ (we have only 'tid' check so far)
>   - l_map->maj, l_map->min, l_map->ino, l_map, ino_generation (we could probably group these)
> 
> and init sort order with:
> 
>    sort_order = "physid,pid,...";
> 
> '...' is whatever name you choose for above entries

The problem is (as you can see in the code above), physid is _not_ just
one piece of data.  It is dependent on multiple things.  It is mainly
dependent on four things:

- cpumode
- major, minor, inode, inode_generation (call it mmap2 data)
- data address
- pid

If cpumode == KERNEL, sort in this order
  - mmap2 data
  - data address
  - pid (optional)

If cpumode == USERSPACE and mmap2 data != 0, sort in this order
  - mmap2 data
  - data address
  - pid (optional)

If cpumode == USERSAPCE and mmap2 data == 0, sort in this order
  - pid
  - data address

Notice how sorting on the pid is different depending on the scenario.

I'll agree that sorting on iaddr and tid can be filtered out as a nice to
have.

But in order to sort on physid, you really need lots of pieces.
Otherwise, what do you consider the definition of 'physid'? :-)

Cheers,
Don