I'm not sure what the benefit would be for this. ODP and Linux take a different approach to optimization. Linux tries to be a single implementation optimized for multiple platforms, hence the use of arch directories. ODP, however is a single *specification* optimized across multiple implementations. odp-dpdk is intended to be the optimized implementation for x86, just as the implementations provided by Cavium, TI, etc. are designed to be the optimized implementations for their respective platforms. As such, linux-generic has no need for platform-specific optimizations, however organized.
On Mon, Mar 9, 2015 at 7:50 AM, Mike Holmes <[email protected]> wrote: > > > On 9 March 2015 at 08:45, Savolainen, Petri (Nokia - FI/Espoo) < > [email protected]> wrote: > >> Performance is not the main concern here, but cycle count measurement >> accuracy. E.g. Intel rdtsc cycle counter read latency is few cycles where >> as clock_gettime() seems to take over a thousand. System call latencies >> also vary since those may launch other kernel services, which adds jitter >> to cycle count measurements. >> >> >> >> Could we organize arch specific stuff better (no #ifdefs, but >> configure/build mechanism) and continue to support e.g. rdtsc. >> > > We had originally proposed an arch directory to capture architecture > differences that should be common to all X86, ARM etc regardless of the > platform and its specific accelerators. > If this were at the top in odp/arch then I would imaging they would be > reusable implementations of API functions. > > I think this should be a topic for the ARCH call in 10 mins. > > >> >> >> -Petri >> >> >> >> >> >> *From:* [email protected] [mailto: >> [email protected]] *On Behalf Of *ext Bill Fischofer >> *Sent:* Friday, March 06, 2015 6:42 PM >> *To:* Mike Holmes >> *Cc:* lng-odp >> *Subject:* Re: [lng-odp] [PATCH] linux-generic: time: remove platform >> specific acceleration >> >> >> >> I agree with Mike. Now that we have an official LNG performance >> implementation, linux-generic should focus on being a simple and clean >> functional implementation that elaborates the intended behavior of the ODP >> APIs without being overly concerned with performance. That doesn't mean we >> don't do straightforward functional optimizations that are algorithmic in >> nature, just that there shouldn't be any platform-specific tuning paths in >> linux-generic. >> >> >> >> On Fri, Mar 6, 2015 at 10:35 AM, Mike Holmes <[email protected]> >> wrote: >> >> The DPDK implementation will take the X86 optimizations, presumably >> Cavium already have Octeon acceleration in their own ODP implementation. >> >> >> >> The linux generic implementation should be a model for the behavior of >> ODP, it happens to run in Linux but that should not be confused with it >> being used in any real application. >> >> >> >> If we fill it with optimizations it will be harder to maintain as a pure >> model. >> >> >> >> Mike >> >> >> >> On 6 March 2015 at 11:26, Maxim Uvarov <[email protected]> wrote: >> >> Where should be that implementations placed if we want other platform to >> reuse them? >> >> Maxim. >> >> >> >> On 03/06/15 19:22, Mike Holmes wrote: >> >> Linux-generic should be a reference implementation and does not need >> archetecture specific acceleration. >> >> Signed-off-by: Mike Holmes <[email protected]> >> --- >> platform/linux-generic/odp_time.c | 47 >> +++------------------------------------ >> 1 file changed, 3 insertions(+), 44 deletions(-) >> >> diff --git a/platform/linux-generic/odp_time.c >> b/platform/linux-generic/odp_time.c >> index 31d6656..6f40361 100644 >> --- a/platform/linux-generic/odp_time.c >> +++ b/platform/linux-generic/odp_time.c >> @@ -6,52 +6,13 @@ >> #define _POSIX_C_SOURCE 200809L >> +#include <time.h> >> #include <odp/time.h> >> -#include <odp/hints.h> >> #include <odp/system_info.h> >> - >> -#define GIGA 1000000000 >> - >> -#if defined __x86_64__ || defined __i386__ >> - >> -uint64_t odp_time_cycles(void) >> -{ >> - union { >> - uint64_t tsc_64; >> - struct { >> - uint32_t lo_32; >> - uint32_t hi_32; >> - }; >> - } tsc; >> - >> - __asm__ __volatile__ ("rdtsc" : >> - "=a" (tsc.lo_32), >> - "=d" (tsc.hi_32) : : "memory"); >> - >> - return tsc.tsc_64; >> -} >> - >> - >> -#elif defined __OCTEON__ >> - >> -uint64_t odp_time_cycles(void) >> -{ >> - #define CVMX_TMP_STR(x) CVMX_TMP_STR2(x) >> - #define CVMX_TMP_STR2(x) #x >> - uint64_t cycle; >> - >> - __asm__ __volatile__ ("rdhwr %[rt],$" CVMX_TMP_STR(31) : >> - [rt] "=d" (cycle) : : "memory"); >> - >> - return cycle; >> -} >> - >> -#else >> - >> -#include <time.h> >> -#include <stdlib.h> >> #include <odp_debug_internal.h> >> +#define GIGA 1000000000 >> + >> uint64_t odp_time_cycles(void) >> { >> struct timespec time; >> @@ -74,8 +35,6 @@ uint64_t odp_time_cycles(void) >> return cycles; >> } >> -#endif >> - >> uint64_t odp_time_diff_cycles(uint64_t t1, uint64_t t2) >> { >> if (odp_likely(t2 > t1)) >> >> >> >> _______________________________________________ >> lng-odp mailing list >> [email protected] >> http://lists.linaro.org/mailman/listinfo/lng-odp >> >> >> >> >> >> -- >> >> Mike Holmes >> >> Technical Manager - Linaro Networking Group >> >> Linaro.org <http://www.linaro.org/> *│ *Open source software for ARM SoCs >> >> >> >> >> _______________________________________________ >> lng-odp mailing list >> [email protected] >> http://lists.linaro.org/mailman/listinfo/lng-odp >> >> >> > > > > -- > Mike Holmes > Technical Manager - Linaro Networking Group > Linaro.org <http://www.linaro.org/> *│ *Open source software for ARM SoCs > > >
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