> -----Original Message----- > From: Robin Murphy <robin.murphy@xxxxxxx> > Sent: Wednesday, July 13, 2022 3:13 AM > To: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>; Besar Wicaksono > <bwicaksono@xxxxxxxxxx> > Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>; catalin.marinas@xxxxxxx; > will@xxxxxxxxxx; mark.rutland@xxxxxxx; linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux- > tegra@xxxxxxxxxxxxxxx; sudeep.holla@xxxxxxx; > thanu.rangarajan@xxxxxxx; Michael.Williams@xxxxxxx; Thierry Reding > <treding@xxxxxxxxxx>; Jonathan Hunter <jonathanh@xxxxxxxxxx>; Vikram > Sethi <vsethi@xxxxxxxxxx>; mike.leach@xxxxxxxxxx; leo.yan@xxxxxxxxxx > Subject: Re: [RESEND PATCH v3 1/2] perf: coresight_pmu: Add support for > ARM CoreSight PMU driver > > External email: Use caution opening links or attachments > > > On 2022-07-12 17:36, Mathieu Poirier wrote: > [...] > >>> If we have decied to call this arm_system_pmu, (which I am perfectly > >>> happy with), could we please stick to that name for functions that we > >>> export ? > >>> > >>> e.g, > >>> > s/coresight_pmu_sysfs_event_show/arm_system_pmu_event_show()/ > >>> > >> > >> Just want to confirm, is it just the public functions or do we need to > replace > >> all that has "coresight" naming ? Including the static functions, structs, > filename. > > > > I think all references to "coresight" should be changed to > "arm_system_pmu", > > including filenames. That way there is no doubt this IP block is not > > related, and does not interoperate, with the any of the "coresight" IP > blocks > > already supported[1] in the kernel. > > > > I have looked at the documentation[2] in the cover letter and I agree > > with an earlier comment from Sudeep that this IP has very little to do with > any > > of the other CoreSight IP blocks found in the CoreSight framework[1]. > Using the > > "coresight" naming convention in this driver would be _extremely_ > confusing, > > especially when it comes to exported functions. > > But conversely, how is it not confusing to make up completely different > names for things than what they're actually called? The CoreSight > Performance Monitoring Unit is a part of the Arm CoreSight architecture, > it says it right there on page 1. What if I instinctively associate the > name Mathieu with someone more familiar to me, so to avoid confusion I'd > prefer to call you Steve? Is that OK? > What is the naming convention for modules under drivers/perf ? In my observation, the names there correspond to the part monitored by the PMU. The confusion on using "coresight_pmu" naming could be that people may think the PMU monitors coresight system, i.e the trace system under hwtracing. However, the driver in this patch is for a new PMU standard that monitors uncore parts. Uncore was considered as terminology from Intel, so "system" was picked instead. Please see this thread for reference: https://lore.kernel.org/linux-arm-kernel/20220510111318.GD27557@willie-the-truck/ > As it happens, Steve, I do actually agree with you that "coresight_" is > a bad prefix here, but only for the reason that it's too general. TBH I > think that's true of the existing Linux subsystem too, but that damage > is already done, and I'd concur that there's little value in trying to > unpick that now, despite the clear existence of products like CoreSight > DAP and CoreSight ELA which don't have all that much to do with program > trace either. > > However, hindsight and inertia are hardly good reasons to double down on > poor decisions, so if I was going to vote for anything here it would be > "cspmu_", which is about as > obviously-related-to-the-thing-it-actually-is as we can get while also > being pleasantly concise. > > [ And no, this isn't bikeshedding. Naming things right is *important* ] > I agree having the correct name is important, especially at this early stage. A direction of what the naming should describe would be very helpful here. > Cheers, > Robin. > > > > > Thanks, > > Steve > > > > [1]. drivers/hwtracing/coresight/ > > [2]. https://developer.arm.com/documentation/ihi0091/latest
