Re: [PATCH v2 7/7] perf expr: Migrate expr ids table to a hashmap

From: Jiri Olsa <jolsa@redhat.com>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>, Kajol Jain <kjain@linux.ibm.com>,
	Andi Kleen <ak@linux.intel.com>,
	John Garry <john.garry@huawei.com>,
	Jin Yao <yao.jin@linux.intel.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Kim Phillips <kim.phillips@amd.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Leo Yan <leo.yan@linaro.org>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	bpf@vger.kernel.org, Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH v2 7/7] perf expr: Migrate expr ids table to a hashmap
Date: Sat, 16 May 2020 00:41:39 +0200	[thread overview]
Message-ID: <20200515224139.GB3577540@krava> (raw)
In-Reply-To: <20200515165007.217120-8-irogers@google.com>

On Fri, May 15, 2020 at 09:50:07AM -0700, Ian Rogers wrote:

SNIP

> diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
> index 8b4ce704a68d..f64ab91c432b 100644
> --- a/tools/perf/util/expr.c
> +++ b/tools/perf/util/expr.c
> @@ -4,25 +4,76 @@
>  #include "expr.h"
>  #include "expr-bison.h"
>  #include "expr-flex.h"
> +#include <linux/kernel.h>
>  
>  #ifdef PARSER_DEBUG
>  extern int expr_debug;
>  #endif
>  
> +static size_t key_hash(const void *key, void *ctx __maybe_unused)
> +{
> +	const char *str = (const char *)key;
> +	size_t hash = 0;
> +
> +	while (*str != '\0') {
> +		hash *= 31;
> +		hash += *str;
> +		str++;
> +	}
> +	return hash;
> +}
> +
> +static bool key_equal(const void *key1, const void *key2,
> +		    void *ctx __maybe_unused)
> +{
> +	return !strcmp((const char *)key1, (const char *)key2);

should that be strcasecmp ? would it affect the key_hash as well?

jirka