Re: [RFT 0/3] cxgb4: use request_firmware_nowait()

From: Casey Leedom
Date: Tue Jun 24 2014 - 12:34:51 EST



On 06/24/14 08:55, Casey Leedom wrote:

On 06/23/14 17:29, Luis R. Rodriguez wrote:
On Mon, Jun 23, 2014 at 12:06:48PM -0700, Casey Leedom wrote:

Also, it might be useful if there was a way for the driver
module to "tell" the timeout mechanism that forward progress _is_ being
made so it doesn't blow away the driver module load.
Indeed if this is actually needed, but believe the issue here for the
huge delays might be instead the lack of not using request_firmware_direct()
and actual device initialization time, which I do not believe we penalize,
we should be penalizing only the amount of time it takes either the
kernel or udev to read the firmware from the filesystem.

If you want I can time the actual phases of loading new firmware: request_firmware(), writing it to FLASH, release_firmware() ...

So I just did this for a normal modprobe (after the system is up):

Jiffies Process
-----------------------------------------------------------------------
0 begin firmware load process
3 request_firmware() returns
7 start looking at the adapter
10 finish reading the first sector of existing adapter firmware
26 we've decided that we're going to upgrade the firmware
28 actual firmware upgrade process starts
448 we've finished halting the adapter processor
451 we enter the firmware write routine
8,470 we've finished erasing the firmware FLASH sectors
14,336 write of new firmware is complete
14,340 the new firmware load is complete
14,949 the adapter processor has been restarted; new firmware running
14,952 firmware upgrade process complete

Maybe request_firmware() takes more time during the boot phase but as we can see from the above timings, it's the actual firmware upgrade process which takes the most time ...

Casey
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