Re: [RFC PATCH v2 2/3] plugins: cache: Enabled parameterization and added trace printing

[Mahmoud Mandour <ma.mandourr@gmail.com>]

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CC'ing Emilio

On Sun, May 30, 2021 at 8:37 AM Mahmoud Mandour <ma.mandourr@gmail.com>
wrote:

> Made both icache and dcache configurable through plugin arguments
> and added memory trace printing in a separate file.
>
> Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
> ---
>  contrib/plugins/cache.c | 68 +++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 66 insertions(+), 2 deletions(-)
>
> diff --git a/contrib/plugins/cache.c b/contrib/plugins/cache.c
> index 8c9d1dd538..fa0bf1dd40 100644
> --- a/contrib/plugins/cache.c
> +++ b/contrib/plugins/cache.c
> @@ -22,7 +22,7 @@ static GRand *rng;
>  static GHashTable *dmiss_ht;
>  static GHashTable *imiss_ht;
>
> -static GMutex dmtx, imtx;
> +static GMutex dmtx, imtx, fmtx;
>
>  static int limit;
>  static bool sys;
> @@ -33,6 +33,8 @@ static uint64_t dmisses;
>  static uint64_t imem_accesses;
>  static uint64_t imisses;
>
> +FILE *tracefile;
> +
>  static enum qemu_plugin_mem_rw rw = QEMU_PLUGIN_MEM_RW;
>
>  enum AccessResult {
> @@ -205,6 +207,16 @@ static void vcpu_mem_access(unsigned int cpu_index,
> qemu_plugin_meminfo_t info,
>      insn_addr = ((struct InsnData *) userdata)->addr;
>      effective_addr = hwaddr ? qemu_plugin_hwaddr_phys_addr(hwaddr) :
> vaddr;
>
> +    if (tracefile) {
> +        g_mutex_lock(&fmtx);
> +        g_autoptr(GString) rep = g_string_new("");
> +        bool is_store = qemu_plugin_mem_is_store(info);
> +        g_string_append_printf(rep, "%c: 0x%" PRIx64,
> +                is_store ? 'S' : 'L', effective_addr);
> +        fprintf(tracefile, "%s\n", rep->str);
> +        g_mutex_unlock(&fmtx);
> +    }
> +
>      if (access_cache(dcache, effective_addr) == MISS) {
>          struct InsnData *insn = get_or_create(dmiss_ht, userdata,
> insn_addr);
>          insn->misses++;
> @@ -221,11 +233,20 @@ static void vcpu_insn_exec(unsigned int vcpu_index,
> void *userdata)
>      g_mutex_lock(&imtx);
>      addr = ((struct InsnData *) userdata)->addr;
>
> +    if (tracefile) {
> +        g_mutex_lock(&fmtx);
> +        g_autoptr(GString) rep = g_string_new("");
> +        g_string_append_printf(rep, "I: 0x%" PRIx64, addr);
> +        fprintf(tracefile, "%s\n", rep->str);
> +        g_mutex_unlock(&fmtx);
> +    }
> +
>      if (access_cache(icache, addr) == MISS) {
>          struct InsnData *insn = get_or_create(imiss_ht, userdata, addr);
>          insn->misses++;
>          imisses++;
>      }
> +
>      imem_accesses++;
>      g_mutex_unlock(&imtx);
>  }
> @@ -352,6 +373,15 @@ static void plugin_exit()
>
>      g_mutex_unlock(&dmtx);
>      g_mutex_unlock(&imtx);
> +
> +    if (tracefile) {
> +        fclose(tracefile);
> +    }
> +}
> +
> +static bool bad_cache_params(int blksize, int assoc, int cachesize)
> +{
> +    return (cachesize % blksize) != 0 || (cachesize % (blksize * assoc)
> != 0);
>  }
>
>  QEMU_PLUGIN_EXPORT
> @@ -377,14 +407,48 @@ int qemu_plugin_install(qemu_plugin_id_t id, const
> qemu_info_t *info,
>
>      for (i = 0; i < argc; i++) {
>          char *opt = argv[i];
> -        if (g_str_has_prefix(opt, "limit=")) {
> +        if (g_str_has_prefix(opt, "I=")) {
> +            gchar **toks = g_strsplit(opt + 2, " ", -1);
> +            if (g_strv_length(toks) != 3) {
> +                fprintf(stderr, "option parsing failed: %s\n", opt);
> +                return -1;
> +            }
> +            icachesize = g_ascii_strtoull(toks[0], NULL, 10);
> +            iassoc = g_ascii_strtoull(toks[1], NULL, 10);
> +            iblksize = g_ascii_strtoull(toks[2], NULL, 10);
> +        } else if (g_str_has_prefix(opt, "D=")) {
> +            gchar **toks = g_strsplit(opt + 2, " ", -1);
> +            if (g_strv_length(toks) != 3) {
> +                fprintf(stderr, "option parsing failed: %s\n", opt);
> +                return -1;
> +            }
> +            dcachesize = g_ascii_strtoull(toks[0], NULL, 10);
> +            dassoc = g_ascii_strtoull(toks[1], NULL, 10);
> +            dblksize = g_ascii_strtoull(toks[2], NULL, 10);
> +        } else if (g_str_has_prefix(opt, "limit=")) {
>              limit = g_ascii_strtoull(opt + 6, NULL, 10);
> +        } else if (g_str_has_prefix(opt, "tracefile=")) {
> +            char *file_name = opt + 10;
> +            tracefile = fopen(file_name, "w");
> +            if (!tracefile) {
> +                fprintf(stderr, "could not open: %s for writing\n",
> file_name);
> +            }
>          } else {
>              fprintf(stderr, "option parsing failed: %s\n", opt);
>              return -1;
>          }
>      }
>
> +    if (bad_cache_params(iblksize, iassoc, icachesize)) {
> +        fprintf(stderr, "icache cannot be constructed from given
> parameters\n");
> +        return -1;
> +    }
> +
> +    if (bad_cache_params(dblksize, dassoc, dcachesize)) {
> +        fprintf(stderr, "dcache cannot be constructed from given
> parameters\n");
> +        return -1;
> +    }
> +
>      dcache = cache_init(dblksize, dassoc, dcachesize);
>      icache = cache_init(iblksize, iassoc, icachesize);
>
> --
> 2.25.1
>
>

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