[next] usb_modeswitch_data: install packed database

The packed databased is significantly smaller than the unpacked. The unpacked
database is made of hundreds of small files. So the benefit is larger
filesystems that allocate a minimum of block per file. Database packing adds
some overhead to every invocation of usb_modeswitch. This added overhead
should not be noticeable in practice since usb_modeswitch normally runs only
once per USB device insert event.

Before:

  du -h output/target/usr/share/usb_modeswitch/
  1.9M	output/target/usr/share/usb_modeswitch/

After:

  du -h output/target/usr/share/usb_modeswitch/
  20K	output/target/usr/share/usb_modeswitch/

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
 package/usb_modeswitch_data/usb_modeswitch_data.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Hi Buildroot list,

On Tue, Feb 28, 2017 at 07:37:45AM +0200, Baruch Siach wrote:
> The packed databased is significantly smaller than the unpacked. The unpacked
> database is made of hundreds of small files. So the benefit is larger
> filesystems that allocate a minimum of block per file. Database packing adds
> some overhead to every invocation of usb_modeswitch. This added overhead
> should not be noticeable in practice since usb_modeswitch normally runs only
> once per USB device insert event.

This turns out to be not such a great idea, since our Busybox tar build does 
not support the 'z' command line option. The tcl script embedded in  
usb_modeswitch_dispatcher relies on this option to extract device information 
entries from the packed database.

baruch

> 
> Before:
> 
>   du -h output/target/usr/share/usb_modeswitch/
>   1.9M	output/target/usr/share/usb_modeswitch/
> 
> After:
> 
>   du -h output/target/usr/share/usb_modeswitch/
>   20K	output/target/usr/share/usb_modeswitch/
> 
> Signed-off-by: Baruch Siach <baruch@tkos.co.il>
> ---
>  package/usb_modeswitch_data/usb_modeswitch_data.mk | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/package/usb_modeswitch_data/usb_modeswitch_data.mk b/package/usb_modeswitch_data/usb_modeswitch_data.mk
> index 6d75b3198310..8373b6e2ca20 100644
> --- a/package/usb_modeswitch_data/usb_modeswitch_data.mk
> +++ b/package/usb_modeswitch_data/usb_modeswitch_data.mk
> @@ -14,7 +14,7 @@ USB_MODESWITCH_DATA_LICENSE_FILES = COPYING
>  # Nothing to build, it is a pure data package
>  
>  define USB_MODESWITCH_DATA_INSTALL_TARGET_CMDS
> -	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) DESTDIR=$(TARGET_DIR) install
> +	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) DESTDIR=$(TARGET_DIR) install-packed
>  endef
>  
>  $(eval $(generic-package))

Hello,

On Wed, 1 Mar 2017 11:21:34 +0200, Baruch Siach wrote:

> On Tue, Feb 28, 2017 at 07:37:45AM +0200, Baruch Siach wrote:
> > The packed databased is significantly smaller than the unpacked. The unpacked
> > database is made of hundreds of small files. So the benefit is larger
> > filesystems that allocate a minimum of block per file. Database packing adds
> > some overhead to every invocation of usb_modeswitch. This added overhead
> > should not be noticeable in practice since usb_modeswitch normally runs only
> > once per USB device insert event.  
> 
> This turns out to be not such a great idea, since our Busybox tar build does 
> not support the 'z' command line option. The tcl script embedded in  
> usb_modeswitch_dispatcher relies on this option to extract device information 
> entries from the packed database.

Can we adapt the TCL code to do:

	gunzip -dc <file> | tar -xf -

Thomas

Hi Thomas,

On Wed, Mar 01, 2017 at 10:32:28AM +0100, Thomas Petazzoni wrote:
> On Wed, 1 Mar 2017 11:21:34 +0200, Baruch Siach wrote:
> > On Tue, Feb 28, 2017 at 07:37:45AM +0200, Baruch Siach wrote:
> > > The packed databased is significantly smaller than the unpacked. The unpacked
> > > database is made of hundreds of small files. So the benefit is larger
> > > filesystems that allocate a minimum of block per file. Database packing adds
> > > some overhead to every invocation of usb_modeswitch. This added overhead
> > > should not be noticeable in practice since usb_modeswitch normally runs only
> > > once per USB device insert event.  
> > 
> > This turns out to be not such a great idea, since our Busybox tar build does 
> > not support the 'z' command line option. The tcl script embedded in  
> > usb_modeswitch_dispatcher relies on this option to extract device information 
> > entries from the packed database.
> 
> Can we adapt the TCL code to do:
> 
> 	gunzip -dc <file> | tar -xf -

Of course. But that is something for upstream to deal with. As I'm much more 
time constrained than space constrained at the moment, I'll leave that to 
someone else.

baruch