Hi Tomasz, On Thu, May 15, 2014 at 3:44 PM, Doug Anderson <dianders@xxxxxxxxxxxx> wrote: > Tomasz, > > On Thu, May 15, 2014 at 3:13 PM, Tomasz Figa <tomasz.figa@xxxxxxxxx> wrote: >>> NOTE: if for some reason we need to keep the MCT around, we're >>> definitely going to need to account for the fact that tweaking it >>> affects the arch timer. ...and having the arch timer is really nice >>> since: >> >> [Let me reorder the points below to make it easier to comment:] >> >>> * it's faster to access. >>> * it is accessible from userspace for really fast access. >> >> Do you have some data on whether it is a significant difference, >> especially considering real use cases? > > I know that Chrome makes _a lot_ of calls to gettimeofday() for > profiling purposes, enough that it showed up on benchmarks. In fact, > we made a change to the MCT to make accesses faster and there's a > small mention of the benchmarking that was done at: > > https://chromium-review.googlesource.com/#/c/32190/ > > ...that change probably should be sent upstream, actually. > > I'll let Chirantan comment on how much faster arch timers were. > ...and I think David Riley (also CCed now) may be able to comment on > the benefits of userspace timers. > When I profiled gettimeofday() calls, they were about 50 - 60% faster with the arch timers compared to the mct. - Chirantan -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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