On Wed, 22 Sep 2021 23:35:50 +0000, Al Viro wrote: > On Wed, Sep 22, 2021 at 01:52:18PM +0200, David Disseldorp wrote: > > do_header() is called for each cpio entry and first checks for "newc" > > magic before parsing further. The magic check includes a special case > > error message if POSIX.1 ASCII (cpio -H odc) magic is detected. This > > special case POSIX.1 check needn't be done in the hot path, so move it > > under the non-newc-magic error path. > > You keep refering to hot paths; do you have any data to support that > assertion? The code-path is run for every single initramfs entry on every single boot. Calling that "hot" is reasonable IMO. > How much does that series buy you on average, and what kind of dispersion > do you get before and after it? I withdrew the perf claims for this patch after you rightly pointed out that my previous numbers weren't statistically significant. After doing further checks I noticed that there was more to be gained via the INITRAMFS_PRESERVE_MTIME changes. Numbers for extraction performance with and without mtime preservation can be found in [PATCH 5/5] of this series. > I'm not saying I hate the patches themselves, but those references in commit > messages ping my BS detectors every time I see them ;-/ I'll try harder to strip anything that might be considered buzzwordy in future, sorry. Cheers, David
